Title
The first order definability of graphs with separators via the Ehrenfeucht game
Abstract
We say that a first order formula φ defines a graph G if φ is true on G and false on every grap G' non-isomorphic with G. Let D(G) be the minimum quantifier rank of a such formula. We prove that, if G is a tree of bounded degree or a Hamiltonian (equivalently, 2-connected) outerplanar graph, then D(G) = O (log n), where n denotes the order of G. This bound is optimal up to a constant factor. If h is a constant, for connected graphs with no minor Kh and degree O (√nlog n), we prove the bound D(G) = O (√n). This result applies to planar graphs and, more generally, to graphs of bounded genus.Our proof techniques are based on the characterization of the quantifier rank as the length of the Ehrenfeucht game on non-isomorphic graphs. We use the separator theorems to design a winning strategy for Spoiler in this game.
Year
DOI
Venue
2005
10.1016/j.tcs.2005.05.003
Theor. Comput. Sci.
Keywords
DocType
Volume
bound D,bounded degree,nlog n,grap G,n denotes,graph G,degree O,order definability,bounded genus,log n,Ehrenfeucht game
Journal
343
Issue
ISSN
Citations 
1-2
Theoretical Computer Science
6
PageRank 
References 
Authors
0.54
11
1
Name
Order
Citations
PageRank
Oleg Verbitsky119127.50