Ramsey numbers of partial order graphs (comparability graphs) and implications in ring theory

For a partially ordered set(A, ≤), letGA be the simple, undirected graph with vertex set A such that two vertices a ≠ ∈ b A are adjacent if either a ≤ b or b a ≤ . We call GA the partial order graph or comparability graph of A. Furthermore, we say that a graph G is a partial order graph if there exi...

وصف كامل

محفوظ في:
التفاصيل البيبلوغرافية
المؤلف الرئيسي: Badawi, Ayman (author)
مؤلفون آخرون: Rissner, Roswitha (author)
التنسيق: article
منشور في: 2020
الموضوعات:
الوصول للمادة أونلاين:http://hdl.handle.net/11073/21411
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الوصف
الملخص:For a partially ordered set(A, ≤), letGA be the simple, undirected graph with vertex set A such that two vertices a ≠ ∈ b A are adjacent if either a ≤ b or b a ≤ . We call GA the partial order graph or comparability graph of A. Furthermore, we say that a graph G is a partial order graph if there exists a partially ordered set A such that G = GA. For a class of simple, undirected graphs and n, m ≥ 1, we define the Ramsey number (n m, ) with respect to to be the minimal number of vertices r such that every induced subgraph of an arbitrary graph in consisting of r vertices contains either a complete n-clique Kn or an independent set consisting of m vertices. In this paper, we determine the Ramsey number with respect to some classes of partial order graphs. Furthermore, some implications of Ramsey numbers in ring theory are discussed.