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fix_typos
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shlff committed Jun 4, 2023
commit 08d361ddd4e10f7f557efc54c9cddcae49120c13
13 changes: 7 additions & 6 deletions lectures/supply_demand_heterogeneity.md
Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ While the results of the study were informative, we used a strong simplifying as

In the real world, households, firms and other economic agents differ from one another along many dimensions.

In this lecture, we introduce heterogeneity across consumers by allowing their preferences and endownments to differ.
In this lecture, we introduce heterogeneity across consumers by allowing their preferences and endowments to differ.

We will examine competitive equilibrium in this setting.

Expand Down Expand Up @@ -69,7 +69,7 @@ e_1 + e_2 =
(\Pi^\top \Pi)^{-1}(\Pi^\top (b_1 + b_2) - (\mu_1 + \mu_2) p )
$$

which after a line or two of linear algebra implies that
which, after a line or two of linear algebra, implies that

$$
(\mu_1 + \mu_2) p = \Pi^\top(b_1+ b_2) - \Pi^\top \Pi (e_1 + e_2)
Expand Down Expand Up @@ -122,7 +122,7 @@ To compute a competitive equilibrium of a pure exchange economy, we use the fact

We can use the following steps to compute a competitive equilibrium:

- First we solve the single representative consumer economy by normalizing $\mu = 1$. Then, we renormalize the price vector by using the first consumption good as numeraire.
- First we solve the single representative consumer economy by normalizing $\mu = 1$. Then, we renormalize the price vector by using the first consumption good as a numeraire.

- Next we use the competitive equilibrium prices to compute each consumer's marginal utility of wealth:

Expand Down Expand Up @@ -221,7 +221,7 @@ class ExchangeEconomy:
p = Pi.T @ b - Pi.T @ Pi @ e
p = p / p[0]

# compute marg util of wealth
# compute marginal utility of wealth
mu_s = []
c_s = []
A = p.T @ slope_dc @ p
Expand Down Expand Up @@ -372,7 +372,7 @@ print('Competitive equilibrium allocation:', c_s)
## Deducing a Representative Consumer

In the class of multiple consumer economies that we are studying here, it turns out that there
exists a single **representative consumer** whose preferences and endowments can be deduced from lists of preferences and endowments for the separate individual consumers.
exists a single **representative consumer** whose preferences and endowments can be deduced from lists of preferences and endowments for separate individual consumers.

Consider a multiple consumer economy with initial distribution of wealth $W_i$ satisfying $\sum_i W_{i}=0$

Expand Down Expand Up @@ -440,4 +440,5 @@ $$
p=\tilde{\mu}^{-1}(\Pi^{\top}b-\Pi^{\top}\Pi e)
$$

Thus, we have verified that, up to choice of a numeraire in which to express absolute prices, the price vector in our representative consumer economy is the same as that in an underlying economy with multiple consumers.
Thus, we have verified that, up to the choice of a numeraire in which to express absolute prices, the price
vector in our representative consumer economy is the same as that in an underlying economy with multiple consumers.