CD(4) has bounded width
Catarina Carvalho, Victor Dalmau, Petar Markovic and Miklos Maroti
Algebra Universalis 2007.

Abstract

We prove that the constraint languages invariant under a short sequence of Jónsson terms (containing at most three non-trivial ternary terms) are tractable by showing that they have bounded width. This improves a previous result by Kiss and Valeriote and presents some evidence that the Larose-Zádori conjeture holds in the congruence-distributive case.

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