1. Operations
- operation
- nullary operation
- unary operation
- binary operation
- n-ary operation
- n-arity operation
- equational law
- associative operation
- commutative operation
- distributive operation
2.  Algebraic structures
- algebraic structure
- identity element
- inverse elements
3. Universal homomorphisms
- kernel (universal)
- first isomorphism theorem (universal)
- second isomorphism theorem (universal)
- algebra homomorphism
\chapter{Operators}

\begin{definition}
An \emph{operation} is a function that maps a set to itself; 
\end{definition}