Merge pull request #71 from mathmetal/patch-1

Slightly improved the line on quantifiers.

_chapters/07-ex4.md

@@ -393,7 +393,7 @@ For mutable indexable collections, such as arrays, you can use `sort!()`, which
 
 #### `all()` and `any()`
 
-`all()` and `any()` implement two of the mathematical concepts known as _quantifiers_, with `all()` representing the universal quantifier `\forall`, while `any()` implements the existential quantifier. These functions test whether all or any, respectively, of a collection satisfies a certain criterion, and return a single truth value.
+`all()` and `any()` implement two of the mathematical concepts known as _quantifiers_, with `all()` representing the universal quantifier $$\forall$$, while `any()` implements the existential quantifier $$\exists$$. These functions test whether all or any elements, respectively, of a collection satisfies a certain criterion, and return a single truth value.
 
 #### Existence of a particular value