Seminar

Alternating sign trapezoids and cyclically symmetric lozenge tilings with a central hole

Algebraic and Enumerative Combinatorics

29 January 10:30 - 11:20

Ilse Fischer - University of Vienna

For about 35 years now, combinatorialists have tried to find bijections between three classes of objects that are all counted by the product formula $\prod\limits_{i=0}^{n-1} \frac{(3i+1)!}{(n+i)!}$. These objects are $n \times n$ alternating sign matrices, totally symmetric self-complementary plane partitions in a $2n \times 2n \times 2n$ box, and descending plane partitions with parts at most $n$. Recently, we have added a fourth class of objects to this list, namely alternating sign triangles, and, even more recently, we have extended this class to alternating sign trapezoids, and have shown that they are equinumerous with cyclically symmetric lozenge tilings tilings of a hexagon with a central hole of size $k$. Partly based on joint work with Arvind Ayyer and Roger Behrend
Organizers
Sara Billey
University of Washington
Petter Brändén
KTH Royal Institute of Technology
Sylvie Corteel
Université Paris Diderot, Paris 7
Svante Linusson
KTH Royal Institute of Technology

Program
Contact

Svante Linusson

linusson@math.kth.se

Other
information

For practical matters at the Institute, send an e-mail to administration@mittag-leffler.se