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Published in: Theory of Computing Systems 5/2019

31-10-2018

Counting Edge-injective Homomorphisms and Matchings on Restricted Graph Classes

Authors: Radu Curticapean, Holger Dell, Marc Roth

Published in: Theory of Computing Systems | Issue 5/2019

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Abstract

We consider the #W[1]-hard problem of counting all matchings with exactly k edges in a given input graph G; we prove that it remains #W[1]-hard on graphs G that are line graphs or bipartite graphs with degree 2 on one side. In our proofs, we use that k-matchings in line graphs can be equivalently viewed as edge-injective homomorphisms from the disjoint union of k length-2 paths into (arbitrary) host graphs. Here, a homomorphism from H to G is edge-injective if it maps any two distinct edges of H to distinct edges in G. We show that edge-injective homomorphisms from a pattern graph H can be counted in polynomial time if H has bounded vertex-cover number after removing isolated edges. For hereditary classes \(\mathcal {H}\) of pattern graphs, we complement this result: If the graphs in \(\mathcal {H}\) have unbounded vertex-cover number even after deleting isolated edges, then counting edge-injective homomorphisms with patterns from \(\mathcal {H}\) is #W[1]-hard. Our proofs rely on an edge-colored variant of Holant problems and a delicate interpolation argument; both may be of independent interest.

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Footnotes
1
We need to assume here that the colors of the two identified edges agree.
 
2
That is, r is bounded by dk for some overall constant d.
 
3
Here, x is an indeterminate, so the quantity (7) is a polynomial in x.
 
Literature
1.
go back to reference Cai, J.-Y., Zhiguo, F.: Holographic algorithm with matchgates is universal for planar #CSP over boolean domain. arXiv:abs/1603.07046 (2016) Cai, J.-Y., Zhiguo, F.: Holographic algorithm with matchgates is universal for planar #CSP over boolean domain. arXiv:abs/​1603.​07046 (2016)
4.
12.
go back to reference Curticapean, R.: The Simple, Little and Slow Things Count: on Parameterized Counting Complexity. Saarland University, PhD thesis (2015)MATH Curticapean, R.: The Simple, Little and Slow Things Count: on Parameterized Counting Complexity. Saarland University, PhD thesis (2015)MATH
14.
go back to reference Curticapean, R., Marx, D.: Complexity of counting subgraphs Only the boundedness of the vertex-cover number counts. In: Proceedings of the 55th Annual Symposium on Foundations of Computer Science, FOCS, pp. 130–139, IEEE. https://doi.org/10.1109/FOCS.2014.22 (2014) Curticapean, R., Marx, D.: Complexity of counting subgraphs Only the boundedness of the vertex-cover number counts. In: Proceedings of the 55th Annual Symposium on Foundations of Computer Science, FOCS, pp. 130–139, IEEE. https://​doi.​org/​10.​1109/​FOCS.​2014.​22 (2014)
20.
go back to reference Flum, J., Grohe, M.: Parameterized complexity theory. Springer, Berlin (2006)MATH Flum, J., Grohe, M.: Parameterized complexity theory. Springer, Berlin (2006)MATH
28.
go back to reference Kasteleyn, P.W. : Graph theory and crystal physics. In: Graph Theory and Theoretical Physics, pp. 43–110. Academic Press (1967) Kasteleyn, P.W. : Graph theory and crystal physics. In: Graph Theory and Theoretical Physics, pp. 43–110. Academic Press (1967)
Metadata
Title
Counting Edge-injective Homomorphisms and Matchings on Restricted Graph Classes
Authors
Radu Curticapean
Holger Dell
Marc Roth
Publication date
31-10-2018
Publisher
Springer US
Published in
Theory of Computing Systems / Issue 5/2019
Print ISSN: 1432-4350
Electronic ISSN: 1433-0490
DOI
https://doi.org/10.1007/s00224-018-9893-y

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