@@ -78,7 +78,7 @@ as an **expectational difference equation** whose solution is a rational expecta
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We'll start this lecture with a quick review of deterministic (i.e., non-random)
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first-order and second-order linear difference equations.
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- ## Linear difference equations
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+ ## Linear Difference Equations
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We'll use the * backward shift* or * lag* operator $L$.
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@@ -94,7 +94,7 @@ We'll often use the equality $L^{-1} x_t \equiv x_{t+1}$ below.
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The algebra of lag and forward shift operators can simplify representing and solving linear difference equations.
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- ### First order
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+ ### First Order
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We want to solve a linear first-order scalar difference equation.
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@@ -181,7 +181,7 @@ diverge, in which case a solution of this form does not exist.
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The distributed lead in $u$ in {eq}` equn_5 ` need not
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converge when $|\lambda| < 1$.
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- ### Second order
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+ ### Second Order
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Now consider the second order difference equation
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@@ -351,7 +351,7 @@ equation {eq}`equation_1` can be constructed by adding to the right hand of {eq}
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sequence $c \lambda^{-t}$ where $c$ is an arbitrary positive
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constant.
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- ## Some Python code
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+ ## Some Python Code
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We’ll construct examples that illustrate {eq}` equation_3 ` .
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@@ -464,7 +464,7 @@ Because
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- it happens that in this example future $m$’s are always less
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than the current $m$
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- ## Alternative code
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+ ## Alternative Code
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We could also have run the simulation using the quantecon
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** LinearStateSpace** code.
@@ -498,7 +498,7 @@ plt.legend()
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plt.show()
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```
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- ### Special case
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+ ### Special Case
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To simplify our presentation in ways that will let focus on an important
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idea, in the above second-order difference equation {eq}` equation_6 ` that governs
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Please keep these formulas in mind as we investigate an alternative
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route to and interpretation of our formula for $F$.
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- ## Another perspective
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+ ## Another Perspective
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Above, we imposed stability or non-explosiveness on the solution of the key difference equation {eq}` equation_1 `
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in Cagan's model by solving the unstable root of the characteristic polynomial forward.
@@ -685,7 +685,7 @@ p_0 = - (Q^{22})^{-1} Q^{21} m_0.
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This is the unique ** stabilizing value** of $p_0$ expressed as a function of
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$m_0$.
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- ### Refining the formula
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+ ### Refining the Formula
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We can get an even more convenient formula for $p_0$ that is cast
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in terms of components of $Q$ instead of components of
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Q_1 = \begin{bmatrix} Q_{11} \\ Q_{21} \end{bmatrix}.
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$$
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- ### Some remarks about feedback
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+ ### Remarks about Feedback
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We have expressed {eq}` equation_8 ` in what superficially appears to be a form in
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which $y_ {t+1}$ feeds back on $y_t$, even though what we
@@ -778,7 +778,7 @@ We’ll keep these observations in mind as we turn now to a case in which
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the log money supply actually does feed back on the log of the price
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level.
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- ## Log money supply feeds back on log price level
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+ ## Log money Supply Feeds Back on Log Price Level
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An arrangement of eigenvalues that split around unity, with one being
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below unity and another being greater than unity, sometimes prevails when there is * feedback* from the log price level to the log
@@ -964,7 +964,7 @@ exist.
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magic_p0(1, δ=0.2)
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```
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- ## Big $P$, little $p$ interpretation
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+ ## Big $P$, Little $p$ Interpretation
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It is helpful to view our solutions of difference equations having feedback from the price level or inflation to money or the rate of money
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creation in terms of the Big $K$, little $k$ idea discussed in {doc}` Rational Expectations Models <rational_expectations> ` .
@@ -1064,7 +1064,7 @@ Compare $F^*$ with $F_1 + F_2 F^*$
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F_check[0] + F_check[1] * F_star, F_star
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```
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- ## Fun with SymPy code
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+ ## Fun with SymPy
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This section is a gift for readers who have made it this far.
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