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Tefko Saracevic, Rutgers University
1
Practice for logical operators
Boolean search statements and
Venn diagrams
Tefko Saracevic, Rutgers University
2
Exact match - Boolean search
• You retrieve exactly what you ask for in the query:– all documents that have the term(s)
with logical connection(s), and possible other restrictions (e.g. to be in titles) as stated in the query
– exactly: nothing less, nothing more
• Based on matching following rules of Boolean algebra, or algebra of sets– ‘new algebra’– presented by circles in Venn diagrams
Tefko Saracevic, Rutgers University
3
Boolean algebra & Venn diagrams
Four basic operations:
1 2 3
A BA alone. All documents that have A. Shade 1 & 2. E.G. apples
1 2 3
A B
A AND B. Shade 2
apples AND oranges
1 2 3
A B
A OR B. Shade 1, 2, 3
apples OR oranges
1 2 3
A B
A NOT B. Shade 1
apples NOT oranges
Tefko Saracevic, Rutgers University
4
Venn diagrams … cont.
Complex statements allowed e.g
12
3
4 5 6
7
A B
C
(A OR B) AND C
Shade 4,5,6
(apples or oranges) AND Florida
(A OR B) NOT C
Shade what?
(apples or oranges NOT Florida
Tefko Saracevic, Rutgers University
5
Directions for exercise
• Slide 7 provides a Venn diagram with numbered sets and a number of search statements– for each statement shade the
appropriate set or sets– e.g. for (A OR B) AND C the sets
are 4, 5, 6
• Slide 8 is for practice
• Slide 9 has the answers– BUT NOTE: one of the answers is
WRONG! Which one?
Tefko Saracevic, Rutgers University
6
Order of operations
• Rules for the order in which operations are done effect the answer - so follow them
• Dialog order of operation is: 1. First are done all operations that are in
parentheses, then:
2. (W), (N), (S), (L), or (F)
3. NOT
4. AND
5. OR• e.g. for A OR B AND C, first is done B
AND C, and then A OR the results of B AND C, thus this is the same as A OR (B AND C)
Tefko Saracevic, Rutgers University
7
Venn diagrams
1 2 3
4 5 6
7
A B
C
1. A AND B
2. A OR B
3. A OR B AND C
4. (A OR B) AND C
5. A AND B NOT C
6. A AND (B NOT C)
7. (A AND B) NOT C
8. (A NOT B) AND C
9. A NOT (B AND C)
10. A NOT B AND C
11. A AND (B OR C)
12. A AND B OR C
13. A OR (B AND C)
14. A OR B OR C
15 A AND B AND C
Tefko Saracevic, Rutgers University
8
12
3
4 5 6
7
A B
C
Use for exercise & shading
Tefko Saracevic, Rutgers University
9
1. A AND B 2,5
2. A OR B 1,2,3,4,5,6
3. A OR B AND C 1,2,4,5,6
4. (A OR B) AND C 4,5,6
5. A AND B NOT C 2
6. A AND (B NOT C) 2
7. (A AND B) NOT C 2
8. (A NOT B) AND C 4
9. A NOT (B AND C) 6
10. A NOT B AND C 4
11. A AND (B OR C) 2,4,5
12. A AND B OR C 2,4,5,6,7
13. A OR (B AND C) 1,2,4,5,6
14. A OR B OR C 1,2,3,4,5,6,7
15 A AND B AND C 5
1 2 3
4 5 6
7
A B
C
Venn diagrams: solutionsp.s. one of them is wrong!