q-Inverting pairs of linear transformations and the q-tetrahedron algebra

As part of our study of the q-tetrahedron algebra ⊠q we introduce the notion of a q-inverting pair. Roughly speaking, this is a pair of invertible semisimple linear transformations on a finite-dimensional vector space, each of which acts on the eigenspaces of the other according to a certain rule. Our main result is a bijection between the following two sets: (i) the isomorphism classes of finite-dimensional irreducible ⊠q-modules of type 1; (ii) the isomorphism classes of q-inverting pairs.