The homomorphism domination exponent

Journal Article (Journal Article)

We initiate a study of the homomorphism domination exponent of a pair of graphs F and G, defined as the maximum real number c such that |Hom(F,T)|≥|Hom(G,T)|c for every graph T. The problem of determining whether HDE(F,G)≥1 is known as the homomorphism domination problem, and its decidability is an important open question arising in the theory of relational databases. We investigate the combinatorial and computational properties of the homomorphism domination exponent, proving upper and lower bounds and isolating classes of graphs F and G for which HDE(F,G) is computable. In particular, we present a linear program computing HDE(F,G) in the special case, where F is chordal and G is series-parallel. © 2011 Elsevier Ltd.

Full Text

Duke Authors

Cited Authors

  • Kopparty, S; Rossman, B

Published Date

  • October 1, 2011

Published In

Volume / Issue

  • 32 / 7

Start / End Page

  • 1097 - 1114

International Standard Serial Number (ISSN)

  • 0195-6698

Digital Object Identifier (DOI)

  • 10.1016/j.ejc.2011.03.009

Citation Source

  • Scopus