t-analogues des operateurs d'ecrantage associes aux q-caracteres (t-analogs of screening operators related to q-characters)

Frenkel and Reshetikhin introduced screening operators related to q-characters of finite dimensional representations of quantum affine algebras. We propose t-analogs of screening operators related to Nakajima's q,t-characters with the same properties of symmetry. Nakajima introduced non-commutative rings, so we propose bimodules. Our construction uses only combinatorial definition of q,t-characters, and therefore can be extended to the non-simply laced case.