Skip to main content
5 events
when toggle format what by license comment
Feb 16, 2012 at 19:41 comment added Alexander Braverman Look at Kostant's paper that I mentioned above - he does exactly what you want for the $U$-invariants in $k[U]_C$.
Feb 16, 2012 at 16:13 comment added Chuck Hague (cont'd) In the case of $SL_2$, the construction of Kumar shows that each standard module for $G$ (which in this case is just characterized by its dimension) occurs naturally as a $U$-submodule of $k[U]_L$. I would like to know if something equally nice happens for $k[U]_C$.
Feb 16, 2012 at 16:11 comment added Chuck Hague Thanks for the comments; perhaps this is another way of stating my question: The structure of $k[U]_L$ as a $U$-module can be fruitfully analyzed by a construction involving $G$-modules, so can a similar thing be done to understand $k[U]_C$? In fact the paper of Joseph that I link to above shows that $k[U]_L$ even has the structure of a module for the hyperalgebra of $G$ compatible with the $U$-module structure (the dual zero Verma structure), although I don't expect such a thing occurs for $k[U]_C$. (cont'd)
Feb 16, 2012 at 13:26 history edited Jim Humphreys CC BY-SA 3.0
added 399 characters in body
Feb 15, 2012 at 23:12 history answered Jim Humphreys CC BY-SA 3.0