We define H-fibration sequences as fibrations where the holonomy action of the fundamental group of the base on the fiber lies in a given subgroup H of E(F ), where E(F ) is the homotopy automorphism group of the fiber. ...

The aim of this paper is to show how we can induce contact structures, contact metric structures and Sasaki structures on a null hypersurface from a rigging vector field. We give several explicit examples of this construction ...

For any n ≥ 2 and fixed k ≥ 1, we give necessary and sufficient conditions for an arbitrary nonzero square matrix in the matrix ring Mn(F) to be written as a sum of an invertible matrix U and a nilpotent matrix N with Nk ...

Let D denote the unit disc in C. We define the generalized Cesàro operator as follows: Cω( f )(z) = 1 0 f (t z) 1 z z 0 Bω t (u) du ω(t)dt, where {Bω ζ }ζ∈D are the reproducing kernels of the Bergman space ...

We study some properties of the Gelfand-Kirillov dimension in a non-necessarily unital context. In particular, its Morita invariance when the algebras have local units, and its commutativity with direct limits. We then ...

Given X a finite nilpotent simplicial set, consider the classifying fibrations X → B aut∗ G(X) → B autG(X) and X → Z → B aut∗ π (X) where G and π denote, respectively, subgroups of the free and pointed homotopy classes ...

Let F be a field. We show that given any nth degree monic polynomial q(x) ∈ F[x] and any matrix A ∈ Mn(F) whose trace coincides with the trace of q(x) and consisting in its main diagonal of k 0-blocks of order one, with k ...

We associate an square to any two dimensional evolution algebra. This geomet- ric object is uniquely determined, does not depend on the basis and describes the structure and the behaviour of the algebra. We determine the ...

The starting point of this work is the fact that the class of evolution algebras over a fixed field is closed under tensor product. We prove that, under certain conditions, the tensor product is an evolution algebra if and ...

We study the topology of all possible subsums of the generalized multigeometric series where are fixed positive real numbers and f runs along a certain class of non-negative functions on the unit interval. We detect ...