2019/09/09 by Ryba, Christopher
#FOS: Mathematics #Representation Theory (math.RT)
paper · doi:10.48550/arxiv.1909.04100
Deligne's category \underline\rm Rep(St) is a tensor category depending on a parameter t "interpolating" the categories of representations of the symmetric groups Sn. We construct a family of categories Cλ (depending on a vector of variables λ= (λ1, λ2, …, λl), that may be specialised to values in the ground ring) which are module categories over \underline\rm Rep(St). The categories Cλ are defined over any ring and are constructed by interpolating permutation representations. Further, they admit specialisation functors to Sn-mod which are tensor-compatible with the functors \underline\rm Rep(St) → Sn-mod. We show that Cλ can be presented using the Kostant integral form of Lusztig's universal enveloping algebra U(\mathfrakgl∞), and exhibit a categorification of some stability properties of Kronecker coefficients.