ar X iv : m at h / 03 03 23 6 v 1 [ m at h . D S ] 1 9 M ar 2 00 3 LOCAL RIGIDITY FOR COCYCLES

ar X iv : m at h / 03 03 23 6 v 3 [ m at h . D S ] 1 2 N ov 2 00 3 LOCAL RIGIDITY FOR COCYCLES

In this paper we study perturbations of constant co-cycles for actions of higher rank semi-simple algebraic groups and their lattices. Roughly speaking, for ergodic actions, Zimmer's co-cycle superrigidity theorems implies that the perturbed cocycle is measurably conjugate to a constant cocycle modulo a compact valued cocycle. The main point of this article is to see that a cocycle which is a c...

ar X iv : m at h / 05 03 14 5 v 1 [ m at h . D G ] 8 M ar 2 00 5 RIGIDITY AND FLEXIBILITY IN POISSON GEOMETRY

We study rigidity and flexibility phenomena in the context of Poisson geometry.

ar X iv : h ep - t h / 03 12 24 4 v 1 1 9 D ec 2 00 3 FIAN / TD / 07 – 03 On Sp ( 2 M ) Invariant Green Functions

Explicit form of two-point and three-point Sp (2M) invariant Green functions is found.

ar X iv : m at h / 03 12 22 1 v 1 [ m at h . R A ] 1 1 D ec 2 00 3 three talks on noncommutative geometry

ar X iv : m at h / 02 03 15 3 v 1 [ m at h . O C ] 1 5 M ar 2 00 2 CONTROLLABILITY OF REDUCED SYSTEMS

Sufficient conditions for the controllability of a conservative reduced system are given. Several examples illustrating the theory are also presented.