Geometric Complexity Theory IV: Nonstandard Quantum Group for the Kronecker Problem

The Kronecker coefficient     is the multiplicity of the  -irreducible       in the restriction of the  -irreducible     via the natural map  , where   are  -vector spaces and  . A fundamental open problem in algebraic combinatorics is to find a positive combinatorial formula for these coefficients.

The authors construct two quantum objects for this problem, which they call the nonstandard quantum group and nonstandard Hecke algebra. They show that the nonstandard quantum group has a compact real form and its representations are completely reducible, that the nonstandard Hecke algebra is semisimple, and that they satisfy an analog of quantum Schur-Weyl duality.