AbstractG being a graph, we define its cyclomatic cohesion γ(G). Then, using Tseitin's method (1970), we construct a contradictory formula C(G) and prove our main theorem: Every resolution of C(G) contains, at least, 2γ(G) distinct clauses. A similar result was obtained by Urquhart (1987) with a different method valid only for a specific family of graphs
