Balanced splittings of Semi-free actions of finite groups on homotopy spheres.
We compute Ext-groups between classical exponential functors (i.e. symmetric, exterior or divided powers) and their Frobenius twists. Our method relies on bar constructions, and bridges these Ext-groups with the homology of Eilenberg-Mac Lane spaces.This article completes earlier results of the author, and provides an alternative approach to classical Ext-computations in the category of strict polynomial functors over fields. We also obtain significant Ext-computations for strict polynomial functors...
Let be any compact simply-connected oriented -dimensional smooth manifold and let be any field. We show that the Gerstenhaber algebra structure on the Hochschild cohomology on the singular cochains of , , extends to a Batalin-Vilkovisky algebra. Such Batalin-Vilkovisky algebra was conjectured to exist and is expected to be isomorphic to the Batalin-Vilkovisky algebra on the free loop space homology on , introduced by Chas and Sullivan. We also show that the negative cyclic cohomology ...
We define the concept of a bi-Legendrian connection associated to a bi-Legendrian structure on an almost -manifold . Among other things, we compute the torsion of this connection and prove that the curvature vanishes along the leaves of the bi-Legendrian structure. Moreover, we prove that if the bi-Legendrian connection is flat, then the bi-Legendrian structure is locally equivalent to the standard structure on .