Mr. Douglas P. R. Petrie

Mr. Douglas Mearns Milne

CS 157 : Assignment 2 Douglas R . Lanman

The union-find data structure, utilizing the “union-by-rank” and “path compression” heuristics, is one of the most efficient disjoint-set data structures known [1]. In general, union-find can be applied to any problem in which one must determine membership within a set. For instance, in class we studied its application within Kruskal’s algorithm, where it was used to efficiently detect connecte...

Petrie-Coxeter Maps Revisited

This paper presents a technique for constructing new chiral or regular polyhedra (or maps) from self-dual abstract chiral polytopes of rank 4. From improperly self-dual chiral polytopes we derive “Petrie-Coxeter-type” polyhedra (abstract chiral analogues of the classical Petrie-Coxeter polyhedra) and investigate their groups of automorphisms.

Mr. R. G. Paul

was a graduate of Edinburgh University in 1927. He became a Fellow of the Royal College of Surgeons in Edinburgh, and was very proud when he was elected Fellow of the Royal College of Surgeons of England (ad eundem) in 1959. In addition, Mr. Paul became a Fellow of the Association of Surgeons of Great Britain, and a member of the council. He was a member and past president of the Moynihan Chiru...

I Am a Strange Loop by Douglas R. Hofstadter

Can thought arise out of matter? Can self, soul, consciousness, “I” arise out of mere matter? If it cannot, then how can you or I be here? I Am a Strange Loop argues that the key to understanding selves and consciousness is the “strange loop”—a special kind of abstract feedback loop inhabiting our brains. The most central and complex symbol in your brain is the one called “I.” The “I” is the ne...