Introduction
Category
Examples of Categories
More Examples
Extra Material
Functor
Examples of Functors
More Examples
Natural Transformation
Examples
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Monad
Monad Examples
More Examples Exception Monad
State Machine Monad
State Machine (cont'd)
Monads in Programming References
Haskell IO 
A monad in category C is an endofunctor F: C → C with two natural transformations: u: 1 → F and m: F ∘ F → F.
Let's denote F(u): F > F ∘ F the transformation that results in applying F to u, and F(m) : (F ∘ F) ∘ F → F ∘ F.
Having these, now we can write down the following two monad axioms:
 F(u) ∘ m is identity F → F
:
 F(m) ∘ m is the same as m ∘ m:

