Markus Pflaum (University of Colorado, Boulder) Introduction to Lie groupoids from a geometric point of view
Apr. 23, 2019 1pm (MATH 220)
Keith Kearnes (CU) Congruence n-permutability is not join prime, 2
Apr. 23, 2019 2pm (MATH 220)
Agnes Szendrei (CU Boulder) Flexible Ultrafilters and the Theory of the Random Graph, Part 2
Apr. 23, 2019 2pm (MATH 350)
Lie Theory
Nathan Lindzey (CU)
X
We discuss a Hecke algebra associated with the permutation representation of the symmetric group acting on the set of matchings of the complete graph. This permutation representation is reminiscent of a more complicated representation that arises when deciding the semi-simplicity of Brauer algebras (see Hanlon & Wales), but our motivation comes from optimization, namely, symmetric semidefinite relaxations of the perfect matching problem. Realizing this Hecke algebra as a non-commutative matrix algebra, we give combinatorial formulas for many of the eigenvalues of operators in this algebra. This is joint work in progress with Gary Au and Levent Tunçel.