巴罗 宏观经济学现代观点 第16章.pptx

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The New Keynesian Model
2 Extensions:
petition:
the typical producer actively sets its price.
Sticky prices:
nominal goods prices that do not react rapidly to changed circumstances.
menu cost
Journal price
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The New Keynesian Model
Price Setting Under petition
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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The New Keynesian Model
Price Setting Under petition
Typically, q(j) depends on relative price P( j )/P

and
the e of consumers
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Extra: Price Setting Under petition
Pure Monopoly
A single seller, who chooses price and quantity to maximize profits.
Entry into the market pletely blocked by technological or legal barriers.
The monopolist’s profit-maximization problem:
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Extra: Price Setting Under petition
FOC:
is the elasticity of market demand at output .
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Extra: Price Setting Under petition
Cournot Oligopoly:
The choice variable is the quantity.
All firms choose simultaneously.
J identical firms produce a homogeneous good.
Their cost function is same:
The inverse market demand is :
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Extra: Price Setting Under petition
The profit function of firm j is:
FOC:
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Extra: Price Setting Under petition
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Extra: Price Setting Under petition
Under petition, 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
firm j ‘s markup ratio
= P( j)/MC( j)
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Extra: Price Setting Under petition
P( j) = (markup ratio) · MC( j)
The production function for firm j looks like the function we have used before:
Y( j) = F[κ( j) · K( j) , L( j) ]
MPL( j) = ∆Y( j)/ ∆L( j)