Vertex-colored graphs, bicycle spaces and Mahler measure
The space [Formula: see text] of conservative vertex colorings (over a field [Formula: see text]) of a countable, locally finite graph [Formula: see text] is introduced. When [Formula: see text] is connected, the subspace [Formula: see text] of based colorings is shown to be isomorphic to the bicycle space of the graph. For graphs [Formula: see text] with a cofinite free [Formula: see text]-action by automorphisms, [Formula: see text] is dual to a finitely generated module over the polynomial ring [Formula: see text]. Polynomial invariants for this module, the Laplacian polynomials [Formula: see text], are defined, and their properties are discussed. The logarithmic Mahler measure of [Formula: see text] is characterized in terms of the growth of spanning trees.