Merge branch 'dev' of github.com:plfa/plfa.github.io into dev

src/plfa/Lists.lagda

@@ -696,7 +696,7 @@ postulate
 ## Monoids
 
 Typically when we use a fold the operator is associative and the
-value is a left and right identity for the value, meaning that the
+value is a left and right identity for the operator, meaning that the
 operator and the value form a _monoid_.
 
 We can define a monoid as a suitable record type:

src/plfa/Properties.lagda

@@ -498,7 +498,7 @@ the variable appears in `Δ`.
 
 * If the term is a lambda abstraction, use the previous lemma to
 extend the map `ρ` suitably and use induction to rename the body of the
-abstraction
+abstraction.
 
 * If the term is an application, use induction to rename both the
 function and the argument.