Combinatorial bases in quantum toroidal $\mathfrak{gl}_2$ modules
Michio Jimbo, Evgeny Mukhin
TL;DR
The paper develops a general combinatorial framework for constructing tame modules of the quantum toroidal gl_2 algebra via balanced q-characters and labeled colored plane partitions. It proves a main theorem that a data pair (S,\Psi) under a set of axioms yields a tame irreducible E-module V(S,\Psi), with explicit action defined by residues at pole locations. This framework is instantiated in numerous explicit examples, including vector and Fock representations, Macmahon plane-partition modules, and a hierarchy of evaluation Verma, relaxed Verma, and slanted relaxed Verma modules, each with concrete l-weight data and character formulas. The results unify and extend known combinatorial constructions while enabling new tame modules, highlighting rich connections to plane partitions, Macmahon formulas, and potential extensions to higher rank algebras and integrable-system applications.
Abstract
We show that many tame modules of the quantum toroidal $\mathfrak{gl}_2$ algebra can be explicitly constructed in a purely combinatorial way using the theory of $q$-characters. The examples include families of evaluation modules obtained from analytic continuation and automorphism twists of Verma modules of the quantum affine $\mathfrak{gl}_2$ algebra. The combinatorial bases in the modules are labeled by colored plane partitions with various properties.
