Abstract
We completely classify the computational complexity of the list H-colouring problem for graphs (with possible loops) in combinatorial and algebraic terms: for every graph H, 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.
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Egri, L., Krokhin, A., Larose, B. et al. The Complexity of the List Homomorphism Problem for Graphs. Theory Comput Syst 51, 143–178 (2012). https://doi.org/10.1007/s00224-011-9333-8
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DOI: https://doi.org/10.1007/s00224-011-9333-8