Petter Restadh: A Generalization of the Inclusion-Exclusion Principle

Abstract

Most mathematicians are familiar with the inclusion-exclusion principle, but have not been introduced to the more general Möbius inversion principle. This principle is commonplace within combinatorics and often used in other areas as well, without being recognized. We will start by introducing partially ordered sets to then take the algebraic approach to Möbius inversion. We will end by discussing some applications of this theorem.