The maximum number of edges in a graph of bounded dimension, with applications to ring theory

نویسندگان

  • Geir Agnarsson
  • Stefan Felsner
  • William T. Trotter
چکیده

With a nite graph G V E we associate a partially ordered set P X P with X V E and x e in P if and only if x is an endpoint of e in G This poset is called the incidence poset of G In this paper we consider the function M p d de ned for p d as the maximum number of edges a graph G can have when it has p vertices and the dimension of its incidence poset is at most d It is easy to see that M p p as only the subgraphs of paths have incidence posets with dimension at most Also a well known theorem of Schnyder asserts that a graph is planar if and only if its incidence poset has dimension at most So M p p for all p In this paper we use the product ramsey theorem Tur an s theorem and the Erd os Stone Theorem to show that limp M p p We then derive some ring theoretic consequences of this in terms of minimal rst syzygies and Betti numbers for monomial ideals

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عنوان ژورنال:
  • Discrete Mathematics

دوره 201  شماره 

صفحات  -

تاریخ انتشار 1999