Jónsson term

In universal algebra, within mathematics, a majority term, sometimes called a Jónsson term, is a term t with exactly three free variables that satisfies the equations t(x, x, y) = t(x, y, x) = t(y, x, x) = x.

In general, Jónsson terms, more formally, a sequence of Jónsson terms, is a sequence of ternary terms satisfying certain related identities.

One of the earliest Maltsev condition, a variety is congruence distributive if and only if it has a sequence of Jónsson terms.

[2] The case of a majority term is given by the special case n=2 of a sequence of Jónsson terms.

[3] Jónsson terms are named after the Icelandic mathematician Bjarni Jónsson.