comparison sort

A comparison sort is a type of sorting algorithm that only reads the list elements through a single abstract comparison operation (often a "less than or equal to" operator or a three-way comparison) that determines which of two elements should occur first in the final sorted list. The only requirement is that the operator obey two of the properties of a total order:

1. if a = b and b = c then a = c (transitivity)
2. for all a and b, either a = b or b = a (totalness or trichotomy).