.1. For any category , possibly enriched over schemes, define to be the functor category with direct sum inherited from . (If is enriched over schemes, like is since it's enriched over itself and vector spaces are schemes, then I probably only want functors that preserve this.) So it's easy to define irrep, etc. of .
Fun fact: consider the irreps of , called the Schur functors. If we restrict them to reps of the single-object category (i.e. monoid) , some irreps restrict to , and the ones that don't go to stay irreducible and give all the irreps of exactly once! In standard indexing, the Schur functors correspond to partitions, the partitions with more than rows restrict to , and the partitions with rows give the irreps of .
.2. I am told that one of the nice properties of Lusztig's canonical basis { } of is that on any irrep of with high weight vector , the nonzero give a basis of .
Is there a common framework for these two facts, perhaps involving categorifying the second one?
(I don't have anything riding on the answer... it's just a question I'd thought of a number of years ago and was reminded of by another mO question.)
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