The space of bi-invariant orders on a nilpotent group

(c,1,...,1) Polynilpotent Multiplier of some Nilpotent Products of Groups

In this paper we determine the structure of (c,1,...,1) polynilpotent multiplier of certain class of groups. The method is based on the characterizing an explicit structure for the Baer invariant of a free nilpotent group with respect to the variety of polynilpotent groups of class row (c,1,...,1).

Faithful actions of automorphisms on the space of orderings of a group

In this article we study the space of leftand bi-invariant orderings on a torsion-free nilpotent group G. We will show that generally the set of such orderings is equipped with a faithful action of the automorphism group of G. We prove a result which allows us to establish the same conclusion when G is assumed to be merely residually torsion-free nilpotent. In particular, we obtain faithful act...

On the Nilpotent Multiplier of a Free Product

Reconstructing Quasimorphisms from Associated Partial Orders and a Question of Polterovich

We show by elementary combinatorial arguments that any non-zero homogeneous quasimorphism on a given group can be realized as the relative growth of some bi-invariant partial order on that group. Thereby we provide a link between quasimorphisms, bounded cohomology and partial orders. This yields existence results for bi-invariant partial orders, e.g. for non-elementary Gromov hyperbolic groups....

SEMIGROUP ACTIONS , WEAK ALMOST PERIODICITY, AND INVARIANT MEANS

Let S be a topological semigroup acting on a topological space X. We develop the theory of (weakly) almost periodic functions on X, with respect to S, and form the (weakly) almost periodic compactifications of X and S, with respect to each other. We then consider the notion of an action of Son a Banach space, and on its dual, and after defining S-invariant means for such a space, we give a...