The University of Michigan Combinatorics Seminar


Abstract 

Several years ago Terry Tao and I introduced a LittlewoodRichardson
rule based on counting "puzzles", and gave a rather unsatisfying proof
that it worked. In this talk I'll connect puzzles very directly to
Vakil's geometric LittlewoodRichardson rule, showing in particular
that all the Grassmannian subschemes in his construction are reduced
and CohenMacaulay. With some new puzzle pieces, we can extend Vakil's
work to equivariant Ktheory of Grassmannians.
