============================== Bar-Ilan Combinatorics Seminar ============================== The next meeting of the seminar will take place, IYH, on (when) Tuesday, 3 Sivan (May 26) 12:00-13:30 (where) Room 201 (Math Dept Seminar Room), Math and CS Building (216), Bar-Ilan University (who) Dan Romik (Hebrew University) will talk about (what) "New enumeration results for alternating sign matrices" Abstract: Alternating sign matrices (ASMs) were discovered by Robbins and Rumsey in the early 1980's in connection with their study of a 19th-century algorithm for computing matrix determinants. They have since been found to have fascinating properties and connections to lattice models in combinatorics and statistical physics, such as: plane partitions, domino tilings, square ice, and 3-colorings of s quare lattices. Two early conjectures of Robbins, Mills and Rumsey about the enumeration of ASMs of order N - both the total enumeration and the so-called refined enumeration with respect to a natural parameter indexing the first row of the matrix - became famous open problems and were resolved in the mid-1990's by Zeilberger. In this talk I will describe recent results on a more detailed "doubly-refined" enumeration of ASMs with respect to the first two rows of the matrix, and a conjectural extension of these results to a "k-tuply refined" enumeration with respect to an arbitrary initial number k of rows. The talk is based on joint works with Ilse Fischer and Matan Karklinsky. Forthcoming Events: ------------------- * 10 Sivan (June 2) Steve Tanny (University of Toronto): "Meta-Fibonacci recursions: Hofstadter, Conolly and much more" ************************************************************************* You are all invited ! (Graduate students especially welcome) If you want to give a talk at the seminar, or know a prospective speaker, please contact Ron Adin . Seminar's homepage: *************************************************************************