Boston University Algebra Seminar

Boston University Algebra Seminar -- Fall 2006


The Andrews-Garvan-Dyson crank and partition congruences


Karl Mahlburg
MIT


Monday, October 30th at 4:15pm
111 Cummington Street, MCS B33


Abstract

In 1944 Freeman Dyson proposed the existence of a crank function that would combinatorially explain the Ramanujan congruences for the partition function. Dyson's call wasn't answered until 1987, when Garvan and Andrews devised a combinatorial interpretation of some interesting q-series in Ramanujan's "Lost Notebook", and showed that this statistic decomposed the three congruences in a natural way. However, in 2000 Ono greatly expanded the subject by proving the existence of infinite families of congruences, again raising the question of finding combinatorial explanations for the new congruences. The present work shows that the crank continues to act as a sort of "universal" statistic for partition congruences, and satisfies exactly the same general congruence properties as the partition function.