Characterizations of biselective operations

Abstract

Let $X$ be a nonempty set and let $i,j\in \{1,2,3,4\}$. We say that a binary operation $F:X^2\to X$ is $(i,j)$-selective if $$F(F(x_1,x_2),F(x_3,x_4))=F(x_i,x_j),$$ for all $x_1,x_2,x_3,x_4\in X$. In this paper we provide characterizations of the class of $(i,j)$-selective operations. We also investigate some subclasses by adding algebraic properties such as associativity or bisymmetry.

18 pages, 6 figures