%0 Journal Article %T The Combinatorics of Polynomial Functors %A Qimh Richey Xantcha %J Mathematics %D 2012 %I arXiv %X We propose a new description of Endofunctors of Module Categories, based upon a combinatorial category comprising finite sets and so-called mazes. Polynomial and numerical functors both find a natural interpretation in this frame-work. Since strict polynomial functors, according to the work of Salomonsson, are encoded by multi-sets, the two strains of functors may be compared and contrasted through juxtaposing the respective combinatorial structures, leading to the Polynomial Functor Theorem, giving an effective criterion for when a numerical (polynomial) functor is strict polynomial. %U http://arxiv.org/abs/1211.6035v2