High Quality Content by WIKIPEDIA articles! In mathematics, two elements x and y of a set partially ordered by a relation <= are said to be comparable if and only if x <= y or y <= x (or in terms of the strict version of the partial order, if and only if x < y or y < x or y = x). For example, two sets are comparable with respect to inclusion if and only if one is a subset of the other. The comparability relation is denoted by the falsum symbol " ". Comparability forms a symmetric relation: x y if and only if y x. Its complement is called incomparablility and denoted by "||". Thus, for every pair of elements x and y of a partially ordered set, exactly one of the following two assertions holds: x y and x || y.

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