High Quality Content by WIKIPEDIA articles! In logic and mathematics, relation reduction and relational reducibility have to do with the extent to which a given relation is determined by an indexed family or a sequence of other relations, called the relation dataset. The relation under examination is called the reductandum. The relation dataset typically consists of a specified relation over sets of relations, called the reducer, the method of reduction, or the relational step, plus a specified set of other relations, simpler in some measure than the reductandum, called the reduciens or the relational base.