Four-angle Hopf modules for Hom-Hopf algebras

Abstract: We introduce the notion of a four-angle $H$-Hopf module for a Hom-Hopf algebra $(H,\beta)$ and show that the category $!^{H}{H}\mathfrak{M}^{H}{H}$ of four-angle $H$-Hopf modules is a monoidal category with either a Hom-tensor product $\otimes_{H}$ or a Hom-cotensor product $\Box_{H}$ as a monoidal product. We study the category $\mathcal{YD}^{H}_{H}$ of Yetter-Drinfel'd modules with bijective structure map can be organized as a braided monoidal category, in which we use a new monoidal structure and prove that if the canonical braiding of the category $\mathcal{YD}^{H}_{H}$ is symmetry then $(H,\beta)$ is trivial. We then prove an equivalence between the monoidal category $(~!^{H}{H}\mathfrak{M}^{H}{H},\otimes_{H})$ or $(~!^{H}{H}\mathfrak{M}^{H}{H},\Box_{H})$ of four-angle $H$-Hopf modules, and the monoidal category $\mathcal{YD}^{H}_{H}$ of Yetter-Drinfel'd modules, and furthermore, we give a braiding structure of the monoidal categorys $(~!^{H}{H}\mathfrak{M}^{H}{H},\otimes_{H})$ (and $(~!^{H}{H}\mathfrak{M}^{H}{H},\Box_{H})$). Finally, we prove that when $(H,\beta)$ is finite dimensional Hom-Hopf algebra, the category $!^{H}{H}\mathfrak{M}^{H}{H}$ is isomorphic to the representation category of Heisenberg double $H^{*op}\otimes H^{*}#H\otimes H^{op}$.