<mathematics> An equivalence class is a subset whose elements are related to each other by an equivalence relation. The equivalence classes of a set under some relation form a partition of that set (i.e. any two are either equal or disjoint and every element of the set is in some class).
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Nearby terms: equational logic « Equational Programming Language « Equel « equivalence class » equivalence class partitioning » equivalence partitioning » equivalence relation