Bound graph

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In graph theory, a bound graph expresses which pairs of elements of some partially ordered set have an upper bound. Rigorously, any graph G is a bound graph if there exists a partial order ≤ on the vertices of G with the property that for any vertices u and v of G, uv is an edge of G if and only if u ≠ v and there is a vertex w such that u ≤ w and v ≤ w.

Bound graphs are sometimes referred to as upper bound graphs, but the analogously defined lower bound graphs comprise the exact same class—any lower bound for ≤ is easily seen to be an upper bound for the dual partial order ≥.

[edit] References

  • McMorris, F.R.; Zaslavsky, T. (1982). "Bound graphs of a partially ordered set". Journal of Combinatorics, Information & System Sciences 7: 134–138. 
  • Lundgren, J.R.; Maybee, J.S. (1983). "A characterization of upper bound graphs". Congressus Numerantium 40: 189–193. 
  • Bergstrand, D.J.; Jones, K.F. (1988). "On upper bound graphs of partially ordered sets". Congressus Numerantium 66: 185–193.