A Geometric Zero-One Law
Abstract
Each relational structure X has an associated Gaifman graph, which endows X with the properties of a graph. Suppose that X is infinite, connected and of bounded degree. A first-order sentence in the language of X is almost surely true (resp. a.s. false) for finite substructures of X if for every element x in X, the fraction of substructures of the ball of radius n around x which satisfy the sentence approaches 1 (resp. 0) as n approaches infinity. Suppose further that, for every finite substructure, X has a disjoint isomorphic substructure. Then every sentence is a.s. true or a.s. false for finite substructures of X. This is one form of the geometric zero-one law. We formulate it also in a form that does not mention the ambient infinite structure. In addition, we investigate various questions related to the geometric zero-one law.
Cite
@article{arxiv.0706.0271,
title = {A Geometric Zero-One Law},
author = {Robert H. Gilman and Yuri Gurevich and Alexei Miasnikov},
journal= {arXiv preprint arXiv:0706.0271},
year = {2007}
}