Fundamental Theorem of Equivalence Relations

The fundamental theorem of equivalence relations states that an equivalence relation on a set partitions that set, and conversely that any partition of a set corresponds to an equivalence relation on that set whose equivalence classes are exactly the cells of that partition. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/