Monoid is a concept that comes from mathematics. We will take a look at it in more detail with all the theory needed to understand it later in this book. For now, it will be enough to remember that a monoid is an algebraic structure with a single associative binary operation and an identity element. Here are the keywords that you should remember:
- The associative binary operation. This means (a+b)+c = a+(b+c).
- The identity element. This means a+i = i+a = a. Here, the identity is i.
What is important about monoids is that they give us the possibility to work with many different types of values in a common way. They allow us to convert pairwise operations to work with sequences; the associativity gives us the possibility for parallelization, ...
