Durfee Square Areas and Associated Partition Identities

Aubrey Blecher1, Arnold Knopfmacher2, Augustine Munagi3
1SCHOOL OF MATHEMATICS, UNIVERSITY OF THE WITWATERSRAND, P. O. Wits, 2050 JOHANNESBURG, SOUTH AFRICA
2THE JOHN KNOPFMACHER CENTRE FOR APPLICABLE ANAL- sis AND NUMBER THEORY, SCHOOL OF MATHEMATICS, UNIVERSITY OF THE WITWATER- SRAND, P. O. Wits, 2050 JOHANNESBURG, SOUTH AFRICA
3THE JOHN KNOPFMACHER CENTRE FOR APPLICABLE ANALY- SIS AND NUMBER THEORY, UNIVERSITY OF THE WITWATERSRAND, P. O. WITS, 2050 JOHANNESBURG, SOUTH AFRICA

Abstract

A partition of an integer \(n\) is a representation \(n = a_1 + a_2 + \cdots + a_k\), with integer parts \(a_1 \geq a_2 \geq \cdots \geq a_k \geq 1\). The Durfee square is the largest square of points in the graphical representation of a partition. We consider generating functions for the sum of areas of the Durfee squares for various different classes of partitions of \(n\). As a consequence, interesting partition identities are derived. The more general case of Durfee rectangles is also treated, as well as the asymptotic growth of the mean area over all partitions of \(n\).