Replace Greek letters with LaTeX (hmemcpy#294)

* Replace Greek letters with LaTeX

* Fix typo

src/content/1.4/kleisli-categories.tex

@@ -334,7 +334,7 @@ \section{Writer in Haskell}
 
 \src{snippet04}
 The result is a lambda function of one argument \code{x}. The lambda
-is written as a backslash --- think of it as the Greek letter λ with an
+is written as a backslash --- think of it as the Greek letter $\lambda$ with an
 amputated leg.
 
 The \code{let} expression lets you declare auxiliary variables. Here
@@ -443,4 +443,4 @@ \section{Challenge}
   Compose the functions \code{safe\_root} and \code{safe\_reciprocal} to implement
   \code{safe\_root\_reciprocal} that calculates \code{sqrt(1/x)}
   whenever possible.
-\end{enumerate}
+\end{enumerate}

src/content/2.4/representable-functors.tex

@@ -165,12 +165,12 @@ \section{Representable Functors}
 
 Let's analyze the definition of the representable functor from this
 perspective. For $F$ to be representable we require that: There
-be an object $a$ in $\cat{C}$; one natural transformation α from
-$\cat{C}(a, -)$ to $F$; another natural transformation, β, in
+be an object $a$ in $\cat{C}$; one natural transformation $\alpha$ from
+$\cat{C}(a, -)$ to $F$; another natural transformation, $\beta$, in
 the opposite direction; and that their composition be the identity
 natural transformation.
 
-Let's look at the component of α at some object $x$. It's a
+Let's look at the component of $\alpha$ at some object $x$. It's a
 function in $\Set$:
 \[\alpha_x \Colon \cat{C}(a, x) \to F x\]
 The naturality condition for this transformation tells us that, for any

src/content/3.11/kan-extensions.tex

@@ -67,7 +67,7 @@
 If the Kan extension $F = Ran_{K}D$ exists, there must be a unique
 natural transformation $\sigma$ from $F'$ to it, such
 that $\varepsilon'$ factorizes through $\varepsilon$, that is:
-\[\varepsilon' = \varepsilon\ .\ (σ \circ K)\]
+\[\varepsilon' = \varepsilon\ .\ (\sigma \circ K)\]
 Here, $\sigma \circ K$ is the horizontal composition of two natural
 transformations (one of them being the identity natural transformation
 on $K$). This transformation is then vertically composed with
@@ -476,4 +476,4 @@ \section{Free Functor}
 \src{snippet11}
 It's easy to check that this is indeed a functor:
 
-\src{snippet12}
+\src{snippet12}

src/content/3.2/adjunctions.tex

@@ -128,7 +128,7 @@ \section{Adjunction and Unit/Counit Pair}
 \end{figure}
 
 \noindent
-By the same token, the component of the counit ε can be described as:
+By the same token, the component of the counit $\varepsilon$ can be described as:
 \[\varepsilon_{c} \Colon (L \circ R) c \to c\]
 It tells us that we
 can pick any object $c$ in $\cat{C}$ as our target, and use the
@@ -271,7 +271,7 @@ \section{Adjunctions and Hom-Sets}
 we have two objects in $\cat{D}$, $d$ and $R c$. They,
 too, define a hom set:
 \[\cat{D}(d, R c)\]
-We say that $L$ is left adjoint to $R$ iff there is an
+We say that $L$ is left adjoint to $R$ if there is an
 isomorphism of hom sets:
 \[\cat{C}(L d, c) \cong \cat{D}(d, R c)\]
 that is natural both in $d$ and $c$.

src/content/3.6/monads-categorically.tex

@@ -450,8 +450,8 @@ \section{Monads from Adjunctions}
 \end{gather*}
 Immediately we see that the unit of an adjunction looks just like the
 unit of a monad. It turns out that the endofunctor $R \circ L$ is
-indeed a monad. All we need is to define the appropriate μ to go with
-the η. That's a natural transformation between the square of our
+indeed a monad. All we need is to define the appropriate $\mu$ to go with
+the $\eta$. That's a natural transformation between the square of our
 endofunctor and the endofunctor itself or, in terms of the adjoint
 functors:
 \[R \circ L \circ R \circ L \to R \circ L\]

src/content/3.7/comonads.tex

@@ -223,7 +223,7 @@ \section{Comonad Categorically}
 
 Defining a comonad in category theory is a straightforward exercise in
 duality. As with the monad, we start with an endofunctor \code{T}. The
-two natural transformations, η and μ, that define the monad are simply
+two natural transformations, $\eta$ and $\mu$, that define the monad are simply
 reversed for the comonad:
 \begin{align*}
 \varepsilon &\Colon T \to I \\
@@ -238,7 +238,7 @@ \section{Comonad Categorically}
 vice versa. And, since the composition $R \circ L$ defines a monad,
 $L \circ R$ must define a comonad. The counit of the adjunction:
 \[\varepsilon \Colon L \circ R \to I\]
-is indeed the same ε that we see in the definition of the comonad ---
+is indeed the same $\varepsilon$ that we see in the definition of the comonad ---
 or, in components, as Haskell's \code{extract}. We can also use the
 unit of the adjunction:
 \[\eta \Colon I \to R \circ L\]