The notion of centrality for crossed modules was introduced by Norrie in her thesis [7], in which she studied the category of crossed modules CM from an algebraic point of view, showing suitable generalizations of group theoretic concepts and results. Subsequently, Norrie’s approach was followed by Carrasco, Cegarra and R.-Grandjeán. In [5] they proved that CM is an algebraic category (i.e. the...

We introduce a hybrid backlight module, which consists of a hybrid light guide plate (HLGP) and a brightness enhancement film (BEF). The HLGP comprises functions of a conventional light guide plate, a reflector, and a BEF. The HLGP allows one-dimensional rays to be collimated. We add a BEF above the HLGP, and let the crossed-dimension rays to be collimated. Comparing with the conventional edge-...

We extend our work in [1] to the case of Hopf comodule coalgebras. We introduce the cocylindrical module C♮H, where H is a Hopf algebra with bijective antipode and C is a Hopf comodule coalgebra over H. We show that there exists an isomorphism between the cocyclic module of the crossed coproduct coalgebra C>◭H and ∆(C♮H), the cocyclic module related to the diagonal of C♮H. We approximate HC(C >...

A holomorphic quadratic differential on a hyperbolic Riemann surface has an associated measured foliation, which can be straightened to yield a measured geodesic lamination. On the other hand, a quadratic differential can be considered as the Schwarzian derivative of a CP1 structure, to which one can naturally associate another measured geodesic lamination (using grafting). We compare these two...

In this paper, we study the higher Yang-Mills theory in framework of gauge theory. It was shown that 2-form electromagnetism can be generalized to with group U(1) replaced by a crossed module Lie groups. To extend even structure, develop 3-form 2-crossed First, give an explicit construction non-degenerate symmetric G-invariant forms on algebras. Then, derive 3-Bianchi-Identities for 3-curvature...

In this paper, we give a natural braiding on the universal central extension of Lie crossed module with given in category modules. We also construct braided modules, showing that, when one these constructions exists, both them exist and coincide.