Merge pull request #491 from ptrfrncsmrph/patch-16

Typos

ch13.md

@@ -91,7 +91,7 @@ Map({day: 'night'}).concat(Map({white: 'nikes'})) // Map({day: 'night', white: '
 
 If you stare at these long enough the pattern will pop out at you like a magic eye poster. It's everywhere. We're merging data structures, combining logic, building strings...it seems one can bludgeon almost any task into this combination based interface.
 
-I've use `Map` a few times now. Pardon me if you two weren't properly introduced. `Map` simply wraps `Object` so we can embellish it with some extra methods without altering the fabric of the universe.
+I've used `Map` a few times now. Pardon me if you two weren't properly introduced. `Map` simply wraps `Object` so we can embellish it with some extra methods without altering the fabric of the universe.
 
 
 ## All my favourite functors are semigroups.
@@ -162,7 +162,7 @@ Map({clicks: Sum(2), path: ['/home', '/about'], idleTime: Right(Max(2000))}).con
 // Map({clicks: Sum(3), path: ['/home', '/about', '/contact'], idleTime: Right(Max(2000))})
 ```
 
-We can stack and combine as many as of these as we'd like. It's simply a matter of adding another tree to the forest, or another flame to the forest fire depending on your codebase.
+We can stack and combine as many of these as we'd like. It's simply a matter of adding another tree to the forest, or another flame to the forest fire depending on your codebase.
 
 The default, intuitive behavior is to combine what a type is holding, however, there are cases where we ignore what's inside and combine the containers themselves. Consider a type like `Stream`:
 
@@ -278,7 +278,7 @@ We'll merge a couple of accounts and keep the `First` id. There is no way to def
 
 ## Group theory or Category theory?
 
-The notion of a binary operation is everywhere in abstract algebra. It is, in fact, the primary operation for a *category*. We cannot, however, model our operation in catgegory theory without an *identity*. This is the reason we start with a semi-group from group theory, then jump to a monoid in category theory once we have *empty*.
+The notion of a binary operation is everywhere in abstract algebra. It is, in fact, the primary operation for a *category*. We cannot, however, model our operation in category theory without an *identity*. This is the reason we start with a semi-group from group theory, then jump to a monoid in category theory once we have *empty*.
 
 Monoids form a single object category where the morphism is `concat`, `empty` is the identity, and composition is guaranteed.