The Complexity of the List Homomorphism Problem for Graphs
We completely classify the computational complexity of the list $\bH$-colouring problem for graphs (with possible loops) in combinatorial and algebraic terms: for every graph $\bH$ the problem is either NP-complete, NL-complete, L-complete or is first-order definable; descriptive complexity equivalents are given as well via Datalog and its fragments. Our algebraic characterisations match important conjectures in the study of constraint satisfaction problems.
Graph homomorphism
constraint satisfaction problem
complexity
universal algebra
Datalog
335-346
Regular Paper
László
Egri
László Egri
Andrei
Krokhin
Andrei Krokhin
Benoit
Larose
Benoit Larose
Pascal
Tesson
Pascal Tesson
10.4230/LIPIcs.STACS.2010.2467
Creative Commons Attribution-NoDerivs 3.0 Unported license
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