2 papers
math.CO2009
Applying the Cluster Method to Count Occurrences of Generalized Permutation Patterns
Andrew M. Baxter
We apply ideas from the cluster method to q-count the permutations of a multiset according to the number of occurrences of certain generalized patterns, as defined by Babson and St…
math.DS2005
Periodic Orbits of Billiards on an Equilateral Triangle
Andrew M. Baxter, Ron Umble
We give a complete solution of the following problem: Find, classify and count the (classes of) periodic orbits on an equilateral triangle. We prove that Fagnano's period 3 orbit i…