Group Actions

On the topological centers of module actions

In this paper, we  study the Arens regularity properties of module actions. We investigate some properties of topological centers of module actions ${Z}^ell_{B^{**}}(A^{**})$ and  ${Z}^ell_{A^{**}}(B^{**})$ with some conclusions in group algebras.

Reiter’s Properties for the Actions of Locally Compact Quantum Goups on von Neumann Algebras

The category of generalized crossed modules

In the definition of a crossed module $(T,G,rho)$, the actions of the group $T$ and $G$ on themselves are given by conjugation. In this paper, we consider these actions to be arbitrary and thus generalize the concept of ordinary crossed module. Therefore, we get the category ${bf GCM}$, of all generalized crossed modules and generalized crossed module morphisms between them, and investigate som...

Orbit Spaces Arising from Isometric Actions on Hyperbolic Spaces

Let be a differentiable action of a Lie group on a differentiable manifold and consider the orbit space with the quotient topology.  Dimension of is called the cohomogeneity of the action of  on . If is a differentiable manifold  of  cohomogeneity one under the action of  a compact and connected Lie group, then the orbit space is homeomorphic to one of the spaces , , or . In this paper we suppo...

Non-Muslim Physicians in Middle Age Islamic Society: Attitudes, Actions, and Interactions

Non-Muslim (Dhimmi) physicians were in touch with Muslims more than other non-Muslims, in cities, villages, courts, hospitals, and even houses in the middle ages. Therefore, they have been mentioned in Muslims' minds, languages, and life experiences more than others. This paper seeks to analyze the attitudes of Muslims towards these physicians and to investigate the relationship between Muslims...

Group actions on 4-manifolds: some recent results and open questions

A survey of finite group actions on symplectic 4-manifolds is given with a special emphasis on results and questions concerning smooth or symplectic classification of group actions, group actions and exotic smooth structures, and homological rigidity and boundedness of group actions. We also take this opportunity to include several results and questions which did not appear elsewhere.