Pappus's theorem and the modular group
Peripheral Structure of 3-Manifolds
Presentations for the punctured mapping class groups in terms of Artin groups.
Pruning theory and Thurston's classification of surface homeomorphisms
Two dynamical deformation theories are presented – one for surface homeomorphisms, called pruning, and another for graph endomorphisms, called kneading – both giving conditions under which all of the dynamics in an open set can be destroyed, while leaving the dynamics unchanged elsewhere. The theories are related to each other and to Thurston’s classification of surface homeomorphisms up to isotopy.
Pseudofree Actions and the Greedy Algorithm.