(PER) A relation R on a set S where R is symmetric (x R y => y R x) and transitive (x R y R z => x R z) and where there may exist elements in S for which the relation is not defined. A PER is an equivalence relation on the subset for which it is defined, i.e. it is also reflexive (x R x).
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Nearby terms: parsing « Parsley « Partial Differential Equation LANguage « partial equivalence relation » partial evaluation » partial function » partial key