In this paper, we study extended modules for a special class of Ore extensions. We will assume that $R$ is a ring and $A$ will denote the Ore extension $A:=R[x_1, \ldots, x_n:\sigma]$ for which $\sigma$ is an automorphism of $R$, $x_ix_j = x_jx_i$ …
We consider a class of endomorphisms which contains a set of piecewise partially hyperbolic skew-products with a non-uniformly expanding base map. The aimed transformation preserves a foliation which is almost everywhere uniformly contracted with …
In this paper we prove that if E and F are reflexive Banach spaces and G is a closed linear subspace of the space 𝐾(𝐸;𝐹) of all compact linear operators from E into F, then G is either reflexive or non-isomorphic to a dual space. This result …
Pre-Koszul and Koszul algebras were defined by Priddy [15]. There exist some relations between these algebras and the skew PBW extensions defined in [8]. In [24] we gave conditions to guarantee that skew PBW extensions over fields it turns out …
We present many examples of Banach spaces of linear operators and homogeneous polynomials without the approximation property, improving results of Dineen and Mujica (Czechoslovak Math. J. 65(140): 367–374, 2015) and Godefroy and Saphar (Proc Am Math …
We study the one-dimensional Riemann problem for a hyperbolic system of three conservation laws of Temple class. The system is a simplification of a recently proposed system of five conservations laws by Bouchut and Boyaval that models viscoelastic …