The main goal of this paper is to give the first examples of equi-variant aspherical Poincare complexes, that are not realized by group actions on closed aspherical manifolds M. These will also provide new counterexamples to the Nielsen realization problem about lifting homotopy actions of finite groups to honest group actions. Our examples show that one cannot guarantee that a given action of ...

Introduction. A space is aspherical if its universal cover is contractible. Examples of aspherical spaces occur in differential geometry (as complete Riemannian manifolds of nonpositive sectional curvature), in Lie groups (as Γ\G/K where G is a Lie group, K is a maximal compact subgroup and Γ is a discrete torsion-free subgroup), in 3-manifold theory and as certain 2-dimensional cell complexes....

In this paper, Problem 4.17 on R. Kirby’s problem list is solved by constructing infinitely many aspherical 4-manifolds that are homology 4-

In order to research an aspherical liquid lens with simple structure and easy realization, the double-liquid based on planar electrode is designed dielectrophoretic effect. The droplet in dielectric electrophoretic polarized electric field move towards direction of higher intensity under action dielectrophoresis forces. With change applied voltage, forces are also changes, thus contact angle at...