Combinatorial Stokes formulas via minimal resolutions

摘要

We describe an explicit chain map from the standard resolution to the minimal resolution for the finite cyclic group Z(k) of order k. We then demonstrate how such a chain trial) induces a "Z(k)-combinatorial Stokes theorem," which in turn implies "Dold's theorem" that there is no equivariant map from an n-connected to all n-dimensional free Z(k)-complex. Thus we build a combinatorial access road to problems in combinatorics and discrete geometry that have previously been treated with methods from equivariant topology. The special case k = 2 for this is classical; it involves Tucker's (1949) combinatorial lemma which implies the Borsuk-Ulam theorem, its proof via chain complexes by Lefschetz (1949), the combinatorial Stokes formula of Fail ( 1967). and Meunier's work (2006). (C) 2008 Elsevier Inc. All rights reserved.