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Topology of Random Cell Complexes Ben Schweinhart Examples Swatches A Case Study Computational Results Persistent Homology Knotting Conclusion Collaborators Topology of Random Cell Complexes Ben Schweinhart Princeton University December 10, 2014

Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

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Page 1: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Topology of Random Cell Complexes

Ben Schweinhart

Princeton University

December 10, 2014

Page 2: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Presentation Outline

1 Examples

2 Swatches

3 A Case Study

4 Computational Results

5 Persistent Homology

6 Knotting

7 Conclusion

8 Collaborators

Page 3: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Examples

Page 4: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Open Cell Foams

Interesting topology

Very important material in practice, not well understood

Page 5: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Grain Growth

Show movie

Steady state for which scale-free properties haveconverged? Dependence on initial conditions?

Need metric - a nice one is given by considering the localtopology.

Page 6: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Grain Growth

Show movie

Steady state for which scale-free properties haveconverged? Dependence on initial conditions?

Need metric - a nice one is given by considering the localtopology.

Page 7: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Notes on Topology

These systems have interesting topology, but they havenot yet been studied using topological methods.*

Crystallography doesn’t apply to disordered materials.

Plan: First, I will introduce a new, general method toquantify the topology of cell complexes.

Then I will talk about a case study, and discusscomputational results - strong evidence of existence of asteady state.

If I have time, I will briefly describe two other topologicalmethods.

Page 8: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Notes on Topology

These systems have interesting topology, but they havenot yet been studied using topological methods.*

Crystallography doesn’t apply to disordered materials.

Plan: First, I will introduce a new, general method toquantify the topology of cell complexes.

Then I will talk about a case study, and discusscomputational results - strong evidence of existence of asteady state.

If I have time, I will briefly describe two other topologicalmethods.

Page 9: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Notes on Topology

These systems have interesting topology, but they havenot yet been studied using topological methods.*

Crystallography doesn’t apply to disordered materials.

Plan: First, I will introduce a new, general method toquantify the topology of cell complexes.

Then I will talk about a case study, and discusscomputational results - strong evidence of existence of asteady state.

If I have time, I will briefly describe two other topologicalmethods.

Page 10: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Notes on Topology

These systems have interesting topology, but they havenot yet been studied using topological methods.*

Crystallography doesn’t apply to disordered materials.

Plan: First, I will introduce a new, general method toquantify the topology of cell complexes.

Then I will talk about a case study, and discusscomputational results - strong evidence of existence of asteady state.

If I have time, I will briefly describe two other topologicalmethods.

Page 11: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Notes on Topology

These systems have interesting topology, but they havenot yet been studied using topological methods.*

Crystallography doesn’t apply to disordered materials.

Plan: First, I will introduce a new, general method toquantify the topology of cell complexes.

Then I will talk about a case study, and discusscomputational results - strong evidence of existence of asteady state.

If I have time, I will briefly describe two other topologicalmethods.

Page 12: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Presentation Outline

1 Examples

2 Swatches

3 A Case Study

4 Computational Results

5 Persistent Homology

6 Knotting

7 Conclusion

8 Collaborators

Page 13: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Swatches

Key Idea

Quantify the local topology of cell complexes by usingprobability distributions of local configurations.

Used to define a distance on cell complexes. The distancecan be used to, e.g., quantify the variability of cellcomplexes generated in a particular way, compare two cellcomplexes (i.e. experimental results with simulations), ortest convergence to a steady state

Applicable to many different physical systems, computable.

Joint work with Jeremy Mason (Bogazici University) andBob MacPherson (Institute for Advanced Study)

Paper on the arxiv: Topological Similarity of Random CellComplexes, and Applications to Dislocation Networks.

Page 14: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Swatches

Key Idea

Quantify the local topology of cell complexes by usingprobability distributions of local configurations.

Used to define a distance on cell complexes. The distancecan be used to, e.g., quantify the variability of cellcomplexes generated in a particular way, compare two cellcomplexes (i.e. experimental results with simulations), ortest convergence to a steady state

Applicable to many different physical systems, computable.

Joint work with Jeremy Mason (Bogazici University) andBob MacPherson (Institute for Advanced Study)

Paper on the arxiv: Topological Similarity of Random CellComplexes, and Applications to Dislocation Networks.

Page 15: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Swatches

Key Idea

Quantify the local topology of cell complexes by usingprobability distributions of local configurations.

Used to define a distance on cell complexes. The distancecan be used to, e.g., quantify the variability of cellcomplexes generated in a particular way, compare two cellcomplexes (i.e. experimental results with simulations), ortest convergence to a steady state

Applicable to many different physical systems, computable.

Joint work with Jeremy Mason (Bogazici University) andBob MacPherson (Institute for Advanced Study)

Paper on the arxiv: Topological Similarity of Random CellComplexes, and Applications to Dislocation Networks.

Page 16: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Swatches

Key Idea

Quantify the local topology of cell complexes by usingprobability distributions of local configurations.

Used to define a distance on cell complexes. The distancecan be used to, e.g., quantify the variability of cellcomplexes generated in a particular way, compare two cellcomplexes (i.e. experimental results with simulations), ortest convergence to a steady state

Applicable to many different physical systems, computable.

Joint work with Jeremy Mason (Bogazici University) andBob MacPherson (Institute for Advanced Study)

Paper on the arxiv: Topological Similarity of Random CellComplexes, and Applications to Dislocation Networks.

Page 17: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Swatches

Key Idea

Quantify the local topology of cell complexes by usingprobability distributions of local configurations.

Used to define a distance on cell complexes. The distancecan be used to, e.g., quantify the variability of cellcomplexes generated in a particular way, compare two cellcomplexes (i.e. experimental results with simulations), ortest convergence to a steady state

Applicable to many different physical systems, computable.

Joint work with Jeremy Mason (Bogazici University) andBob MacPherson (Institute for Advanced Study)

Paper on the arxiv: Topological Similarity of Random CellComplexes, and Applications to Dislocation Networks.

Page 18: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Regular Cell Complexes

Definition

A Regular Cell Complex is a space built inductively byattaching cells in each dimension (points, line segments, disks,etc). Each cell is glued on by homeomorphisms from theirboundaries into the existing structure.

Page 19: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Graph Representation

Represent a regular cell complex by the adjacency graph ofthe cells, labeled by dimension.

Captures all topological properties.

Page 20: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Graph Representation

Represent a regular cell complex by the adjacency graph ofthe cells, labeled by dimension.

Captures all topological properties.

Page 21: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Swatches

Definition

The swatch at vertex v of radius r is the neighborhood of v ofradius r in the graph distance (every edge has length one).

Page 22: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Swatch Types

Two swatches have the same swatch type if they representthe same topological configuration.

Sub-swatch of a swatch: swatch of smaller radius at thesame root (central vertex).

Page 23: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Swatch Types

Two swatches have the same swatch type if they representthe same topological configuration.

Sub-swatch of a swatch: swatch of smaller radius at thesame root (central vertex).

Page 24: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Cloth

For each r , consider the probability distribution of swatchtypes of radius r at the vertices of a cell complex.

This family of probability distributions is called the clothof the cell complex.

Captures all local topological properties of the cellcomplex.

Page 25: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Cloth

For each r , consider the probability distribution of swatchtypes of radius r at the vertices of a cell complex.

This family of probability distributions is called the clothof the cell complex.

Captures all local topological properties of the cellcomplex.

Page 26: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Cloth

For each r , consider the probability distribution of swatchtypes of radius r at the vertices of a cell complex.

This family of probability distributions is called the clothof the cell complex.

Captures all local topological properties of the cellcomplex.

Page 27: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Tree of Swatches

Connect swatch type of radius r with all subswatch typesof radius r − 1.

The cloth is a weighting on this tree, subject toconsistency conditions.

Page 28: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Tree of Swatches

Connect swatch type of radius r with all subswatch typesof radius r − 1.

The cloth is a weighting on this tree, subject toconsistency conditions.

Page 29: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Distance on Swatches

Distance between two swatches = one over order (# cells)of largest common subswatch, or 0 if they are equal.

d(S1,S2) = 113

Page 30: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Distance on Swatches

Distance between two swatches = one over order (# cells)of largest common subswatch, or 0 if they are equal.

d(S1,S2) = 113

Page 31: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Distance on Cell Complexes

Definition

If C1 and C2 are cell complexes, dr (C1,C2) is the EarthMover’s Distance between the probability distributions atradius r induced by distance on swatches.

Earth Mover’s Distance = the infimum of the costs oftransformations between the two probability distributionson swatch types of radius r .

Cost = amount of probability mass moved between swatchtypes, weighted by swatch distance.

Distance can be used to compare different structures, testconvergence to steady state, iteratively modify structuresto reach a desired state

Page 32: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Distance on Cell Complexes

Definition

If C1 and C2 are cell complexes, dr (C1,C2) is the EarthMover’s Distance between the probability distributions atradius r induced by distance on swatches.

Earth Mover’s Distance = the infimum of the costs oftransformations between the two probability distributionson swatch types of radius r .

Cost = amount of probability mass moved between swatchtypes, weighted by swatch distance.

Distance can be used to compare different structures, testconvergence to steady state, iteratively modify structuresto reach a desired state

Page 33: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Distance on Cell Complexes

Definition

If C1 and C2 are cell complexes, dr (C1,C2) is the EarthMover’s Distance between the probability distributions atradius r induced by distance on swatches.

Earth Mover’s Distance = the infimum of the costs oftransformations between the two probability distributionson swatch types of radius r .

Cost = amount of probability mass moved between swatchtypes, weighted by swatch distance.

Distance can be used to compare different structures, testconvergence to steady state, iteratively modify structuresto reach a desired state

Page 34: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Distance on Cell Complexes

Definition

If C1 and C2 are cell complexes, dr (C1,C2) is the EarthMover’s Distance between the probability distributions atradius r induced by distance on swatches.

Earth Mover’s Distance = the infimum of the costs oftransformations between the two probability distributionson swatch types of radius r .

Cost = amount of probability mass moved between swatchtypes, weighted by swatch distance.

Distance can be used to compare different structures, testconvergence to steady state, iteratively modify structuresto reach a desired state

Page 35: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence of Cell Complexes

Limit distance= d(C1,C2) = limr→∞ dr (C1,C2).

A sequence {Ci} of cell complexes converges if it is aCauchy sequence in d .

Equivalent to all swatch frequencies converging.

Page 36: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence of Cell Complexes

Limit distance= d(C1,C2) = limr→∞ dr (C1,C2).

A sequence {Ci} of cell complexes converges if it is aCauchy sequence in d .

Equivalent to all swatch frequencies converging.

Page 37: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence of Cell Complexes

Limit distance= d(C1,C2) = limr→∞ dr (C1,C2).

A sequence {Ci} of cell complexes converges if it is aCauchy sequence in d .

Equivalent to all swatch frequencies converging.

Page 38: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

The Limit

Theorem

(Benjamini-Schramm Graph Limit) A convergent sequence ofcell complexes gives rise to a limit distribution on the space ofcountable, connected cell complexes a root specified. Thedistance can be extended to the space of these distributions.

Also implies convergence of all local topological properties:those that can be defined in terms of maps from a fixedlabeled graph H into the diagram of Ci .

Reference: Large Networks and Graph Limits

Page 39: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

The Limit

Theorem

(Benjamini-Schramm Graph Limit) A convergent sequence ofcell complexes gives rise to a limit distribution on the space ofcountable, connected cell complexes a root specified. Thedistance can be extended to the space of these distributions.

Also implies convergence of all local topological properties:those that can be defined in terms of maps from a fixedlabeled graph H into the diagram of Ci .

Reference: Large Networks and Graph Limits

Page 40: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

The Limit

Theorem

(Benjamini-Schramm Graph Limit) A convergent sequence ofcell complexes gives rise to a limit distribution on the space ofcountable, connected cell complexes a root specified. Thedistance can be extended to the space of these distributions.

Also implies convergence of all local topological properties:those that can be defined in terms of maps from a fixedlabeled graph H into the diagram of Ci .

Reference: Large Networks and Graph Limits

Page 41: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Presentation Outline

1 Examples

2 Swatches

3 A Case Study

4 Computational Results

5 Persistent Homology

6 Knotting

7 Conclusion

8 Collaborators

Page 42: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Track distance dr to candidate steady state

Discuss other applications of topology to the case study.

Page 43: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Track distance dr to candidate steady state

Discuss other applications of topology to the case study.

Page 44: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Track distance dr to candidate steady state

Discuss other applications of topology to the case study.

Page 45: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Track distance dr to candidate steady state

Discuss other applications of topology to the case study.

Page 46: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Track distance dr to candidate steady state

Discuss other applications of topology to the case study.

Page 47: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

The Model

Curvature-driven evolution of polygonal curves in T3.

The polygonal curves meet each other at vertices ofdegree three.

The curves are composed of line segments meeting atnodes.

Evolves by energy minimization, assuming constant energyγ per unit length.

This can be viewed as a very simple model of a dislocationnetwork in the process of recovery.

Page 48: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

The Model

Curvature-driven evolution of polygonal curves in T3.

The polygonal curves meet each other at vertices ofdegree three.

The curves are composed of line segments meeting atnodes.

Evolves by energy minimization, assuming constant energyγ per unit length.

This can be viewed as a very simple model of a dislocationnetwork in the process of recovery.

Page 49: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

The Model

Curvature-driven evolution of polygonal curves in T3.

The polygonal curves meet each other at vertices ofdegree three.

The curves are composed of line segments meeting atnodes.

Evolves by energy minimization, assuming constant energyγ per unit length.

This can be viewed as a very simple model of a dislocationnetwork in the process of recovery.

Page 50: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

The Model

Curvature-driven evolution of polygonal curves in T3.

The polygonal curves meet each other at vertices ofdegree three.

The curves are composed of line segments meeting atnodes.

Evolves by energy minimization, assuming constant energyγ per unit length.

This can be viewed as a very simple model of a dislocationnetwork in the process of recovery.

Page 51: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

The Model

Curvature-driven evolution of polygonal curves in T3.

The polygonal curves meet each other at vertices ofdegree three.

The curves are composed of line segments meeting atnodes.

Evolves by energy minimization, assuming constant energyγ per unit length.

This can be viewed as a very simple model of a dislocationnetwork in the process of recovery.

Page 52: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Movie

Page 53: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Topological Moves

Edge Flip

Digon Deletion

Edge Intersection

Page 54: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Topological Moves

Edge Flip

Digon Deletion

Edge Intersection

Page 55: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Topological Moves

Edge Flip

Digon Deletion

Edge Intersection

Page 56: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Initial Conditions

Voronoi Graph: modified 1-skeleton of Voronoi tesselationfor random points in the three-torus.

Random Graph: Place random points on the three-torus.Randomly create edges between pairs that are closeenough.

Both evolve to “steady state”.

Page 57: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Initial Conditions

Voronoi Graph: modified 1-skeleton of Voronoi tesselationfor random points in the three-torus.

Random Graph: Place random points on the three-torus.Randomly create edges between pairs that are closeenough.

Both evolve to “steady state”.

Page 58: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Initial Conditions

Voronoi Graph: modified 1-skeleton of Voronoi tesselationfor random points in the three-torus.

Random Graph: Place random points on the three-torus.Randomly create edges between pairs that are closeenough.

Both evolve to “steady state”.

Page 59: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Presentation Outline

1 Examples

2 Swatches

3 A Case Study

4 Computational Results

5 Persistent Homology

6 Knotting

7 Conclusion

8 Collaborators

Page 60: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Find candidate steady state for which many scale-freeproperties appear to have converged.

Track distance dr to candidate steady state

Page 61: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Find candidate steady state for which many scale-freeproperties appear to have converged.

Track distance dr to candidate steady state

Page 62: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Find candidate steady state for which many scale-freeproperties appear to have converged.

Track distance dr to candidate steady state

Page 63: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Find candidate steady state for which many scale-freeproperties appear to have converged.

Track distance dr to candidate steady state

Page 64: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Idea of Computation

Simulate curvature-driven evolution of dimension onenetwork in 3-space.

Represent network as one-dimensional cell complex.

Compute cloth (swatch distributions) for radius r < 10

Find candidate steady state for which many scale-freeproperties appear to have converged.

Track distance dr to candidate steady state

Page 65: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence Results, I

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

xh106

0

0.005

0.01

0.015

0.02

0.025

0.03

Timesteps

Dis

tanc

ehto

hTes

thCas

eh(r

=7)

RandomhGraphhInitialhConditions,h208KhEdges

Track distance to large, steady state test case as systemevolves.

Change coordinates to aid comparison of systems.

Page 66: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence Results, I

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

x7105

0

0.005

0.01

0.015

0.02

0.025

0.03

Number7of7Edges

Dis

tanc

e7to

7Tes

t7Cas

e7,r

=78

Random7Graph7Initial7Conditions,7208K7Edges

Track distance to large, steady state test case as systemevolves.

Change coordinates to aid comparison of systems.

Page 67: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence Results, II

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

x7105

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

Number7of7Edges

Dis

tanc

e7to

7Tes

t7Cas

e7,r

=78

Random7Graph7Initial7Conditions,7208K7Edges

First Case: Random Graph Initial Conditions

Page 68: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence Results, II

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

x7105

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

Number7of7Edges

Dis

tanc

e7to

7Tes

t7Cas

e7,r

=78

Random7Graph7Initial7ConditionsM7208K7EdgesVoronoi7Initial7Conditions7M75M7Edges

Second Case: Large Voronoi

Page 69: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence Results, II

102

103

104

105

106

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

Number7of7Edges

Dis

tanc

e7to

7Tes

t7Cas

e7,r

=78

Random7Graph7Initial7ConditionsM7208K7EdgesVoronoi7Initial7Conditions7M75M7Edges

Second Case: Large Voronoi

Page 70: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence Results, II

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

x7105

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

Number7of7Edges

Dis

tanc

e7to

7Tes

t7Cas

e7,r

=78

Random7Graph7Initial7ConditionsM7208K7EdgesVoronoi7Initial7Conditions7M75M7Edges

Second Case: Large Voronoi

Page 71: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence Results, II

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

x7105

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

Number7of7Edges

Dis

tanc

e7to

7Tes

t7Cas

e7,r

=78

Random7Graph7Initial7ConditionsM7208K7EdgesVoronoi7Initial7Conditions7M75M7EdgesVoronoi7Initial7ConditionsM7200K7Edges

Third Case: Small Voronoi

Page 72: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Convergence Results, II

0 0O5 1 1O5 2 2O5 3 3O5 4 4O5

x7105

0

0O005

0O01

0O015

0O02

0O025

0O03

0O035

0O04

0O045

0O05

Number7of7Edges

Dis

tanc

e7to

7Tes

t7Cas

e7,r

=78

Random7Graph7Initial7ConditionsM7208K7EdgesVoronoi7Initial7Conditions7M75M7EdgesVoronoi7Initial7ConditionsM7200K7EdgesRG7Int’l7Cond’nsM7448K7EdgesM7Intersections7Off

Fourth Case: Random Graph with Intersections Disabled

Page 73: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

On Intersections

0 0.5 1 1.5 2 2.5 3 3.5 4

xl105

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

NumberloflEdges

Pro

port

ionl

oflT

opol

ogic

allE

vent

sIntersections

EdgelFlips

DigonlDeletions

Plot preponderance of different topological changes assimulation proceeds.Intersections computationally expensive; can disregard forbetter steady state statistics.

Page 74: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

On Intersections

0 0.5 1 1.5 2 2.5 3 3.5 4

xl105

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

NumberloflEdges

Pro

port

ionl

oflT

opol

ogic

allE

vent

sIntersections

EdgelFlips

DigonlDeletions

Plot preponderance of different topological changes assimulation proceeds.Intersections computationally expensive; can disregard forbetter steady state statistics.

Page 75: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Error Estimation

0 1 2 3 4 5

x)104

0

1

2

3

4

5

6

7

8x)10

−3

Number)of)Edges

Dis

tanc

e)Rr

=7G

Voronoi)Initial)Conditions,)5M)EdgesVoronoi)Initial)Conditions,)200K)EdgesRandom)Graph)Initial)Conditions,)208K)Edges

Hard to estimate statistical error for cloth: complicatedinterdependencies of swatch frequenciesIdea: compare simulation to representative subsamples oftest case

Page 76: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Error Estimation

0 1 2 3 4 5

x)104

0

1

2

3

4

5

6

7

8x)10

−3

Number)of)Edges

Dis

tanc

e)Rr

=7G

Voronoi)Initial)Conditions,)5M)EdgesVoronoi)Initial)Conditions,)200K)EdgesRandom)Graph)Initial)Conditions,)208K)Edges

Hard to estimate statistical error for cloth: complicatedinterdependencies of swatch frequenciesIdea: compare simulation to representative subsamples oftest case

Page 77: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Error Estimation, II

0 1 2 3 4 5

x)104

0

1

2

3

4

5

6

7

8x)10

−3

Number)of)Edges

Dis

tanc

e)Rr

=7G

Voronoi)Initial)Conditions,)5M)EdgesVoronoi)Initial)Conditions,)200K)EdgesRandom)Graph)Initial)Conditions,)208K)Edges

System has converged to state represented by test case ifit is statistically indistinguishable from a subsample of it.Within one standard deviation of subsamples: goodevidence of convergence.

Page 78: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Error Estimation, II

0 1 2 3 4 5

x)104

0

1

2

3

4

5

6

7

8x)10

−3

Number)of)Edges

Dis

tanc

e)Rr

=7G

Voronoi)Initial)Conditions,)5M)EdgesVoronoi)Initial)Conditions,)200K)EdgesRandom)Graph)Initial)Conditions,)208K)Edges

System has converged to state represented by test case ifit is statistically indistinguishable from a subsample of it.Within one standard deviation of subsamples: goodevidence of convergence.

Page 79: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Presentation Outline

1 Examples

2 Swatches

3 A Case Study

4 Computational Results

5 Persistent Homology

6 Knotting

7 Conclusion

8 Collaborators

Page 80: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

2D Persistent Homology of Objects in 3-space

Consider ε-neighborhoods of X ⊂ R3, Xε.

As ε increases, holes form and disappear.

Persistent Homology tracks these holes as ε increases.

Look at figures in Mathematica

Page 81: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

2D Persistent Homology of Objects in 3-space

Consider ε-neighborhoods of X ⊂ R3, Xε.

As ε increases, holes form and disappear.

Persistent Homology tracks these holes as ε increases.

Look at figures in Mathematica

Page 82: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

2D Persistent Homology of Objects in 3-space

Consider ε-neighborhoods of X ⊂ R3, Xε.

As ε increases, holes form and disappear.

Persistent Homology tracks these holes as ε increases.

Look at figures in Mathematica

Page 83: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

2D Persistent Homology of Objects in 3-space

Consider ε-neighborhoods of X ⊂ R3, Xε.

As ε increases, holes form and disappear.

Persistent Homology tracks these holes as ε increases.

Look at figures in Mathematica

Page 84: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistent Homology, ct’d

Philosophy: use persistent homology to study geometry offixed object.

Paper - “Measuring Shape with Topology” (Journal ofMathematical Physics, joint with R. MacPherson)

Holes in Xε correspond to voids in X

Find voids in materials

Page 85: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistent Homology, ct’d

Philosophy: use persistent homology to study geometry offixed object.

Paper - “Measuring Shape with Topology” (Journal ofMathematical Physics, joint with R. MacPherson)

Holes in Xε correspond to voids in X

Find voids in materials

Page 86: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistent Homology, ct’d

Philosophy: use persistent homology to study geometry offixed object.

Paper - “Measuring Shape with Topology” (Journal ofMathematical Physics, joint with R. MacPherson)

Holes in Xε correspond to voids in X

Find voids in materials

Page 87: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistent Homology, ct’d

Philosophy: use persistent homology to study geometry offixed object.

Paper - “Measuring Shape with Topology” (Journal ofMathematical Physics, joint with R. MacPherson)

Holes in Xε correspond to voids in X

Find voids in materials

Page 88: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistent Homology, Continued

Plot time when hole appears vs time when it disappears

Points on x=y line are noise

Page 89: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistent Homology, Continued

Plot time when hole appears vs time when it disappears

Points on x=y line are noise

Page 90: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

1-skeleton of Voronoi Decomposition

Persistent Homology recovers the cells.

Page 91: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Steady State of CDE Simulation

More surprising voids!

Page 92: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Minimal Cycles

Page 93: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistence Tree

Usual interpretation of Persistent Homology representsthis as two points for two voids

Correct structure: Persistence Tree

Adjacency of minimal cycles?

Page 94: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistence Tree

Usual interpretation of Persistent Homology representsthis as two points for two voids

Correct structure: Persistence Tree

Adjacency of minimal cycles?

Page 95: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Persistence Tree

Usual interpretation of Persistent Homology representsthis as two points for two voids

Correct structure: Persistence Tree

Adjacency of minimal cycles?

Page 96: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Presentation Outline

1 Examples

2 Swatches

3 A Case Study

4 Computational Results

5 Persistent Homology

6 Knotting

7 Conclusion

8 Collaborators

Page 97: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Unknotted Networks

Many embedded graphs from physical systems appear tobe unknotted.

How to measure this?

Page 98: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Unknotted Networks

Many embedded graphs from physical systems appear tobe unknotted.

How to measure this?

Page 99: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Minimal Cycles

0 1 2 3 4 5

xK105

0

0.5

1

1.5

2

2.5

3

3.5

4xK10

−3

NumberKofKEdges

cKo

fKMin

imal

KLoo

psKth

atKa

reKK

notte

d

RGKwithKIntersections,KGraphKDistanceRGKwithKIntersections,KEmbeddedKDistance

Look at shortest cycle containing each edge. Is it knotted?

Start with knotted network, track # of knotted minimalcycles as system evolves.

Curvature-driven evolution appears to unknot networks.

Page 100: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Minimal Cycles

0 1 2 3 4 5

xK105

0

0.5

1

1.5

2

2.5

3

3.5

4xK10

−3

NumberKofKEdges

cKo

fKMin

imal

KLoo

psKth

atKa

reKK

notte

d

RGKwithKIntersections,KGraphKDistanceRGKwithKIntersections,KEmbeddedKDistance

Look at shortest cycle containing each edge. Is it knotted?

Start with knotted network, track # of knotted minimalcycles as system evolves.

Curvature-driven evolution appears to unknot networks.

Page 101: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Minimal Cycles

0 1 2 3 4 5

xK105

0

0.5

1

1.5

2

2.5

3

3.5

4xK10

−3

NumberKofKEdges

cKo

fKMin

imal

KLoo

psKth

atKa

reKK

notte

d

RGKwithKIntersections,KGraphKDistanceRGKwithKIntersections,KEmbeddedKDistance

Look at shortest cycle containing each edge. Is it knotted?

Start with knotted network, track # of knotted minimalcycles as system evolves.

Curvature-driven evolution appears to unknot networks.

Page 102: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Minimal Cycles

0 1 2 3 4 5

xK105

0

1

2

3

4

5

6xK10

−3

NumberKofKEdges

cKo

fKMin

imal

KLoo

psKth

atKa

reKK

notte

d

RGKwithKIntersections,KGraphKDistanceRGKwithKIntersections,KEmbeddedKDistanceRGKw/oKIntersections,KGraphKDistanceRGKw/oKIntersections,KEmbeddedKDistance

Look at shortest cycle containing each edge. Is it knotted?

Start with knotted network, track # of knotted minimalcycles as system evolves.

Curvature-driven evolution appears to unknot networks.

Network unknots even faster if intersections turned off.

Page 103: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Unknottedness

Unknotted networks can contain knots.

Page 104: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Defining Unknottedness

Definition

An embedded graph is unknotted if its complement has thehomotopy type of a graph.

Physical interpretation: equivalent to existence of dualnetwork (important for, i.e., open cell foams).

I’m working on several theoretical questions surroundingthis definition.

Is it equivalent to π1 of the complement being free?

Page 105: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Defining Unknottedness

Definition

An embedded graph is unknotted if its complement has thehomotopy type of a graph.

Physical interpretation: equivalent to existence of dualnetwork (important for, i.e., open cell foams).

I’m working on several theoretical questions surroundingthis definition.

Is it equivalent to π1 of the complement being free?

Page 106: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Defining Unknottedness

Definition

An embedded graph is unknotted if its complement has thehomotopy type of a graph.

Physical interpretation: equivalent to existence of dualnetwork (important for, i.e., open cell foams).

I’m working on several theoretical questions surroundingthis definition.

Is it equivalent to π1 of the complement being free?

Page 107: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Defining Unknottedness

Definition

An embedded graph is unknotted if its complement has thehomotopy type of a graph.

Physical interpretation: equivalent to existence of dualnetwork (important for, i.e., open cell foams).

I’m working on several theoretical questions surroundingthis definition.

Is it equivalent to π1 of the complement being free?

Page 108: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Knotted Materials

Knotted materials may have interesting, useful properties.

Metal-organic frameworks: new, exotic, sometimes knotted

Page 109: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Knotted Materials

Knotted materials may have interesting, useful properties.

Metal-organic frameworks: new, exotic, sometimes knotted

Page 110: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Presentation Outline

1 Examples

2 Swatches

3 A Case Study

4 Computational Results

5 Persistent Homology

6 Knotting

7 Conclusion

8 Collaborators

Page 111: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Conclusion

Interesting topology abounds in materials science andphysics.

Topology could be useful for understanding structures thatare currently not well-understood using any methods.

Many applications to work on, many new methods to bedeveloped.

Perhaps the study of these applications will also providenew ideas for topology.

Page 112: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Conclusion

Interesting topology abounds in materials science andphysics.

Topology could be useful for understanding structures thatare currently not well-understood using any methods.

Many applications to work on, many new methods to bedeveloped.

Perhaps the study of these applications will also providenew ideas for topology.

Page 113: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Conclusion

Interesting topology abounds in materials science andphysics.

Topology could be useful for understanding structures thatare currently not well-understood using any methods.

Many applications to work on, many new methods to bedeveloped.

Perhaps the study of these applications will also providenew ideas for topology.

Page 114: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Conclusion

Interesting topology abounds in materials science andphysics.

Topology could be useful for understanding structures thatare currently not well-understood using any methods.

Many applications to work on, many new methods to bedeveloped.

Perhaps the study of these applications will also providenew ideas for topology.

Page 115: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Presentation Outline

1 Examples

2 Swatches

3 A Case Study

4 Computational Results

5 Persistent Homology

6 Knotting

7 Conclusion

8 Collaborators

Page 116: Topology of Random Cell Complexes - Institute for Advanced Study · Swatch Types Two swatches have the sameswatch typeif they represent the same topological con guration. Sub-swatch

Topology ofRandom CellComplexes

BenSchweinhart

Examples

Swatches

A Case Study

ComputationalResults

PersistentHomology

Knotting

Conclusion

Collaborators

Robert MacPherson (Institute for Advanced Study) - PhDAdvisor

Jeremy Mason (Bogazici University) - Swatches