. . 11

7

,,,,

. . 22

( , ) ( ).

Q

D

D

, ,

. . 33

= - Q :

, , Q = q1 + q2 + ..., :

Q

1- =

1111

1 qQ

Q

1-

q

1 ===

, 1, .

. . 44

13

D1

MR1

D2

D

Q Q2 Q3 Q1

MR

OK

MR2

1

23

4

Q. D1( . (Q1, P1) (Q2, P1). D2. Q3 Q4, ...

Q4

. . 55

D2

D

Q

OK

MR2

MMK

. . 66

,

.

, .

. . 77

1. 2. ( )3. 4. (, ,

)5.

i.

ii. iii. (

)iv. ( )

. . 88

1. 3 4

2. Herfindahl index

: = 20% = 30% = (0.2)2 + (0.3)2 + (0.5)2 = 0.38 = 50%

= 20% = 30% = 0.04 + 0.09 + 0.0625 + 0.0625 = 25% = 0.255 = 25%

=

=

12

2 iS

. . 99

3. (concentration curve)

Lorenz

100

10050%

50%

Gini =

0 Gini 1

+

. . 1010

Lerner

: =

- =

- =

)1/-(1 Z=

Ze1 =

=

=

=

2

2

2

e1

OK - T eT

e -

. . 1111

, , ..

, .

.

. . 1212

.

2 ( ) 3 6.000.

6.000

10.000 10.000

6.000D

ATCMC

Minimum

efficient

scale

P

Q

P

Q1 2 3 4 5 1 2 3 4 5 6() ()

. . 1313

, 4 9.000 .

6.000

10.000 10.000

6.000

MC

ATCMC1P

Q

P

Q1 2 3 4 5 1 2 3 4 5 6

() ()

MR

Profit

D

. . 1414

1 2 3 . 5 7.500. 2 4.5 (2 .). 1 1 . .

1 3 .

. . 1515

10000

80007500 7500

6000

1 2 3 4 50 1 2 3 4 50

ATC ATC

7500

1 2 3 4 50

P P

Q Q

P

Q

D

10000

LossProfit

1 2

. . 1616

:

-: .

(0, 0)(-1, 4.5)-

(4.5, -1) (2,2)

-

1

2

. . 1717

Cournot

.

: = bQ Q = q1 + q2: TCi = ciqi i = 1,2

max 1 = ( bQ)qi ciqi

= bq1 bq2 bq1 c1 = 0

2bq1 bq2 = c1 (1)1

1

q

Cournot

. . 1818

:

2

2

q

= 0 2bq2 bq1 = c2 (2)

1 q1 =

2 q2 =

2

1 q21 -

2bc -

12 q

21 -

2bc -

3bc 2c- q

4bc 2c- q

43

q41

4bc - 2c-2 q

q21

2bc-

21 -

2bc- q

211

211

121

1

121

1

+=

+=

++

=

=

(3)

Cournot

. . 1919

(3) 2 :

b3c2c- q

b6)c2c-2(

122

12

+=

+=

b6cc23c--3

3b

c2c-21

2bc-q

212

2122

+=

=+

=

Cournot

. . 2020

:

q1

q2

2

1

2bc- 1

3bc2c- 21 +

3bc2c- 12 +

2bc- 2

Cournot

. . 2121

Stackelberg

Cournot, . ( ) , .

Stackelberg.

. 2. , :

Stackelberg

. . 2222

b2c2c-q

0 cbq)c(21 0

q

qcq q21

2bc-bbq-

122

2212

2

22221

22max2

+=

=+=

=

q

, , q2 1.

Stackelberg

. . 2323

b4c23c-q

b4c2c2c-2

b2c2c-

21

2bc- q

211

121

1211

+=

+=

=+

=

2 Cournot

C2

S1

1212

C2

S2

q q

b3c2c-

b2c2c-

q q

+>

Stackelberg

. . 2424

.

Cournot :

b3cc-2Q

b3c2c-

b3c2c-qqQ

21c

1221c2

c1

c

=

=+

++

=+=

Stackelberg:

b4c2c-3Q

b2c2c-

b4c23c-qqQ

12s

1221s2

s1

s

=

=+

++

=+=

Stackelberg

. . 2525

>

b3cc-2

b4c2c-3 2112

9 6c2 3c1 > 8 4c1 4c2 2c2 + c1 > 0

Qs > Qc

:

>

b2c-

b3cc-2 121 Qc > Qm

Cournot .

: Qs > Qc > Qm

Stackelberg

. . 2626

Stackelberg :

q1

q2

2

Cournot

2

Stackelberg

m2q

Stackelberg ( ) 1.

m2q

Stackelberg

. . 2727

Cournot .

. . 1 2, 2.

Nash 1 2 2 1.

. . 2828

Nash

(1,2)(0,0)

(0,0)(2,1)

, . Nash .

. .

. . 2929

Nash .

Nash .

1) .

Nash-(, ) (-).

(first-mover advantage).

(1,2)(0,0)

(0,0)(2,1)

. . 3030

2)

. , .

(-1,3)(1,0)

(0,-1)(0,0)

. . 3131

. .

, .

Counot .

. . 3232

() :

. , ( ). 2 , . .

, .

. . 3333

() -

.

(i) tit-for-tat

. .(ii) (tiger strategy)

.

tit-for-tat .