Ranking function

Definice math

A bijection assigning unique number to each element of set $S$. $\text{rank}:S\to \{0,1,\dots ,|S|-1\}$Unrank function is an inverse of the ranking function.

Successor function finds element of a set $s\in T$, given another element of set $t\in T$ for which $\text{rank}(s)=\text{rank}(t)+1.$