We introduce the honeycomb model of BZ polytopes, which calculate Littlewood-Richardson coefficients, the tensor product rule for GL(n). Our main result is the existence of a particularly well-behaved honeycomb with given boundary conditions (choice of triple of representations to be tensored together). This honeycomb is necessarily integral, which proves the "saturation conjecture", extending results of Klyachko to give a complete answer to which L-R coefficients are positive. This in turn has as a consequence Horn's conjecture from 1962 characterizing the spectrum of the sum of two Hermitian matrices.
CITATION STYLE
Knutson, A., & Tao, T. (1999). The honeycomb model of $GL_n(\mathbb C)$ tensor products I: Proof of the saturation conjecture. Journal of the American Mathematical Society, 12(4), 1055–1090. https://doi.org/10.1090/s0894-0347-99-00299-4
Mendeley helps you to discover research relevant for your work.