Extended TQ-relations in the Grothendieck ring K0(O)
Establish the extended TQ-relations in K0(O) for all w ∈ W: for any finite-dimensional simple U_q(ĝ)-module V, after replacing each variable Y_{i,a} in the q-character X_q(V) by the specified product [w(ω_i)]·[L(Y_{−w(ω_i), a q^{−1}})]/[L(Y_{w(ω_i), a q})], the resulting expression, once denominators are cleared, equals [V].
References
Conjecture 7.12. Let w E W and let V be a finite-dimensional simple Uq(g)-module. Replace every variable Yi,a, i E I, appearing in the q-character Xq(V) with Yi,a > [w (i )] [L(Y_(w;),aq-1)] [L(Yw(wi),aq;)] By equating the resulting expression with [V] and clearing the denominators, we obtain an algebraic relation in K0(O).
— Extremal monomial property of q-characters and polynomiality of the X-series
(2504.00260 - Frenkel et al., 31 Mar 2025) in Section 7.4, Conjecture 7.12