Abstract
We classify central extensions of a reductive group G by K3 and BK3, the sheaf of third Quillen K-theory groups and its classifying stack. These turn out to be parametrized by the group of Weyl-invariant quadratic forms on the cocharacter lattice valued in k× and the group of integral Weyl-invariant cubic forms on the cocharacter lattice respectively.
Original language | English |
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Pages (from-to) | 152-182 |
Journal | Journal of Algebra |
Volume | 444 |
Early online date | 26 Aug 2015 |
DOIs | |
Publication status | Published - 15 Dec 2015 |