A syntactical proof of the marriage lemma

Artikel i vetenskaplig tidskrift, 2003

We give a proof of the classical Marriage Lemma (Amer. J. Math. 72 (1950) 214) using completeness of hyperresolution. This argument is purely syntactical, and extends directly to the infinite case. As an application we give a purely syntactical version of a proof that resolution is exponential on the pigeon-hole principle.