fixed backticks in code spans

src/Stlc.lagda

@@ -70,7 +70,7 @@ data Type : Set where
 \end{code}
 
 Terms have six constructs. Three are for the core lambda calculus:
-  * Variables, `\` x`
+  * Variables, `` ` x ``
   * Abstractions, `λ[ x ∶ A ] N`
   * Applications, `L · M`
 and three are for the base type, booleans:
@@ -285,7 +285,7 @@ outermost term is now `if_then_else_`, which is typed using `𝔹-E`. The
     ?2 : ∅ , x ∶ 𝔹 ⊢ true ∶ 𝔹
 
 Again we fill in the three holes by typing C-c C-r in each. Agda observes
-that `\` x`, `false`, and `true` are typed using `Ax`, `𝔹-I₂`, and
+that `` ` x ``, `false`, and `true` are typed using `Ax`, `𝔹-I₂`, and
 `𝔹-I₁` respectively. The `Ax` rule in turn takes an argument, to show
 that `(∅ , x ∶ 𝔹) x = just 𝔹`, which can in turn be specified with a
 hole. After filling in all holes, the term is as above.

src/StlcProp.lagda

@@ -266,7 +266,7 @@ _Proof_: We show, by induction on the proof that `x` appears
   free in `M`, that, for all contexts `Γ`, if `M` is well
   typed under `Γ`, then `Γ` assigns some type to `x`.
 
-  - If the last rule used was `free-\``, then `M = \` x`, and from
+  - If the last rule used was `` free-` ``, then `M = `` `x ``, and from
     the assumption that `M` is well typed under `Γ` we have
     immediately that `Γ` assigns a type to `x`.
 
@@ -452,7 +452,7 @@ we show that if `∅ ⊢ V ∶ A` then `Γ ⊢ N [ x := V ] ∶ B`.
   - If `N` is a variable there are two cases to consider,
     depending on whether `N` is `x` or some other variable.
 
-      - If `N = \` x`, then from `Γ , x ∶ A ⊢ x ∶ B`
+      - If `N = `` `x ``, then from `Γ , x ∶ A ⊢ x ∶ B`
         we know that looking up `x` in `Γ , x : A` gives
         `just B`, but we already know it gives `just A`;
         applying injectivity for `just` we conclude that `A ≡ B`.