Right Coideal Subalgebras of the Borel Part of a Quantized Enveloping Algebra
Right Coideal Subalgebras of the Borel Part of a Quantized Enveloping Algebra
For the Borel part of a quantized enveloping algebra, we classify all right coideal subalgebras for which the intersection with the coradical is a Hopf algebra. The result is expressed in terms of characters of the subalgebras U+[w] of the quantized enveloping algebra, introduced by de Concini, Kac, and Procesi …