Cancellation of ladder graphs in an effective expansion

Abstract

A resummation of ladder graphs is important in cases where infrared, collinear, or light-cone singularities render the loop expansion invalid, especially at high temperature where these effects are often enhanced. It has been noted in some recent examples of this resummation that the ladder graphs are canceled by other types of terms. In this note we show that this cancellation is quite general, and for the most part algebraic.