Alternating sign matrices: at the crossroads of algebra, combinatorics and physics
 
 
Description:  Alternating sign matrices have been introduced by combinatorists in the 80's as an extension of the notion of permutation matrices. A simple formula for the number of such matrices of size n has been conjectured. The resolution of this conjecture has been a very active subject in the 80's and 90's. Miraculous coincidences have been discovered with other classes of combinatorial objects, such as the so-called plane partitions or the tilings of hexagonal regions on the triangular lattice. Another surprise came a few years ago when Razumov and Stroganov discovered experimentally that the sequence given by the number of alternating matrices appears in quantum physics in a spin chain model. Many problems remain open. I will finish the talk with an algebraic approach to this fascinating subject introducing a quadratic algebra defined by some generators and commutation relations.
Area(s):
Start Date:  2008-09-26
Start Time:   17:00
Speaker:  Xavier Viennot (LaBRI, CNRS and Univ. Bordeaux 1, France)
Place:  2.4 - Departamento de Matemática
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