巴罗宏观经济学现代观点第16章PPT课件

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Extra: Price Setting Under Imperfect Competition
FOC: M ( q ) p R ' q q p q c ' q M ( q )C
pq
p' q pq
q
1
c' q
pq1
1
q
c'q
q 1 is the elasticity of market
firm j ‘s markup ratio = P( j)/MC( j)
Macroeconomics Chapter 16
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Extra: Price Setting Under Imperfect Competition
P( j) = (markup ratio) ·MC( j)
The production function for firm j looks like the function we have used before:
Chapter16
Money and Business Cycles II: Sticky Prices and Nominal Wage Rates
Macroeconomics Chapter 16
1
The New Keynesian Model
2 Extensions:
Imperfect competition:
All firms choose simultaneously.
• Their cost function is same: Cqj cq j
• The inverse market demand is :
poeconomics Chapter 16
demand at output .
Macroeconomics Chapter 16
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Extra: Price Setting Under Imperfect Competition
Cournot Oligopoly:
• J identical firms produce a homogeneous good. • The choice variable is the quantity.
Y( j) = F[κ( j) ·K( j) , L( j) ]
MPL( j) = ∆Y( j)/ ∆L( j)
Macroeconomics Chapter 16
11
Extra: Price Setting Under Imperfect Competition
MC(j) = w/ MPL( j) P( j) = (markup ratio) ·[w/ MPL( j)]
Under imperfect competition, each firm can set P( j ) above its nominal marginal cost.
The ratio of P( j ) to the nominal marginal cost is called the markup ratio
Macroeconomics Chapter 16
3
The New Keynesian Model
Price Setting Under Imperfect Competition
Typically, q(j) depends on relative price P( j )/P
and
the income of consumers
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Extra: Price Setting Under Imperfect Competition
The profit function of firm j is:
jqab qkqj cqj
k
FOC: d djjq q acbkjqk2bjq 0 j
qj ac1 qk j
2b 2kj
Macroeconomics Chapter 16
the typical producer actively sets its price.
Sticky prices:
nominal goods prices that do not react rapidly to changed circumstances.
menu cost Journal price
Macroeconomics Chapter 16
12
The New Keynesian Model
Macroeconomics Chapter 16
2
The New Keynesian Model
Price Setting Under Imperfect Competition
Let P( j ) be the price charged for a good by firm j.
the quantity demanded of firm j ’s goods is q( j )
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Extra: Price Setting Under Imperfect Competition
J qk J ac 1J 1 J qk
k1
2b 2
k1
J
qk
J
ac
k1
J 1 b
qj baJc1 j
paJac
J1
pcac
J1
J 1
J
Macroeconomics Chapter 16
9
Extra: Price Setting Under Imperfect Competition
Macroeconomics Chapter 16
4
Extra: Price Setting Under Imperfect Competition
Pure Monopoly
A single seller, who chooses price and quantity to maximize profits.
Entry into the market is completely blocked by technological or legal barriers.
The monopolist’s profit-maximization problem:
maqx pqqcq q
Macroeconomics Chapter 16