Generating clones with conservative near-unanimity operation

Abstract

Due to the Baker-Pixley theorem we know that every clone over a finite domain $A$ containing a near-unanimity operation $g$ is finitely generated. Therefore there exists an integer $k$ such that the clone is generated by its $k$-ary part. In this paper we are interested in the size of $k$ for a fixed $A$ and fixed arity of a conservative $g$. We obtain lower bounds for all arities and they turn out to be sharp for arity three.