Finite domination and Novikov rings. Laurent polynomial rings in two variables

Abstract

Let C be a bounded cochain complex of finitely generated free modules over the Laurent polynomial ring L = R[x,1/x,y,1/y]. The complex C is called R-finitely dominated if it is homotopy equivalent over R to a bounded complex of finitely generated projective R-modules. Our main result characterises R-finitely dominated complexes in terms of Novikov cohomology: C is R-finitely dominated if and only if eight complexes derived from C are acyclic; these complexes are obtained by tensoring C over L with R[[x,y]][1/xy] and R[x,1/x][[y]][1/y], and their variants obtained by swapping x and y, and replacing either indeterminate by its inverse.