The Journal of Symbolic Logic

Research Article

The existence of a near-unanimity term in a finite algebra is decidable

Miklós Maróti

Bolyai Institute, University of Szeged, Aradi Vértanúk Tere 1, H-6720 Szeged, Hungary, E-mail: mmaroti@math.u-szeged.hu

Abstract

We prove that it is decidable of a finite algebra whether it has a near-unanimity term operation, which settles a ten-year-old problem. As a consequence, it is decidable of a finite algebra in a congruence distributive variety whether it admits a natural duality.

(Received February 25 2008)