$8$ -manifolds admitting no differentiable structure

Manifolds admitting stable forms

Special geometries defined by a class of differential forms on manifolds are again in the center of interests of geometers. These interests are motivated by the fact that such a setting of special geometries unifies many known geometries as symplectic geometry and geometries with special holonomy [Joyce2000], as well as other geometries arised in the M-theory [GMPW2004], [Tsimpis2005]. A series...

2 00 7 Manifolds admitting a G̃ 2 - structure

We find a necessary and sufficient condition for a compact 7-manifold to admit a G̃2-structure. As a result we find a sufficient condition for an open 7-manifold to admit a closed 3-form of G̃2-type.

Notes on Differentiable Manifolds

Manifolds of Differentiable Densities

We develop a family of infinite-dimensional (i.e. non-parametric) manifolds of probability measures. The latter are defined on underlying Banach spaces, and have densities of class Ck b with respect to appropriate reference measures. The case k = ∞, in which the manifolds are modelled on Fréchet spaces, is included. The manifolds admit the Fisher-Rao metric and the dually flat geometry of Amari...

Stable Equivalence of Differentiable Manifolds

A natural question, of great generality, various special forms of which are often asked in differential topology, is the following: Let Mi, Mi be differentiable w-manifolds, : M\—»M2 a continuous map which is a homotopy equivalence between M\ and M2. When is there a differentiable isomorphism <3>: Mi—> M2 in the same homotopy class as 0? For example, there is the Poincaré Conjecture which po...