The complexity of counting surjective homomorphisms and compactions

A homomorphism from a graph G to a graph H is a function from the vertices of G to the vertices of H that preserves edges. A homomorphism is surjective if it uses all of the vertices of H and it is a compaction if it uses all of the vertices of H and all of the non-loop edges of H. Hell and Neˇsetˇr...

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Bibliographic Details
Main Authors: Focke, J, Goldberg, L, Zivny, S
Format: Conference item
Published: Society for Industrial and Applied Mathematics 2017