Decomposable mappings from the space of symmetric k-fold tensors over E, ⊗ s,k E, to the space of k-fold tensors over F , ⊗ s,k F , are those linear operators which map nonzero decomposable elements to nonzero decomposable elements. We prove that any decomposable mapping is induced by an injective linear operator between the spaces on which the tensors are defined. Moreover, if the decomposable...

let $mathcal{x}$ be a class of $r$-modules‎. ‎in this paper‎, ‎we investigate ;$mathcal{x}$-injective (projective) and dg-$mathcal{x}$-injective (projective) complexes which are generalizations of injective (projective) and dg-injecti‎‎ve (projective) complexes‎. ‎we prove that some known results can be extended to the class of ;$mathcal{x}$-injective (projective) and dg-$mathcal{x}$-injective ...

We give in this paper conditions for a mapping to be globally injective in a topological vector space.

The modification of the Clarke generalized subdiNerentia1 due to Michel and Penot is a useful tool in determining differentiability properties for certain classes of real functions on a normed linear space. The Glteaux differentiability of any real function can be deduced from the GBteaux differentiability of the norm if the function has a directional derivative which attains a constant related...

For Hilbert space operators A and B, let δAB denote the generalised derivation δAB(X) = AX − XB and let 4AB denote the elementary operator4AB(X) = AXB−X. If A is a pk-quasihyponormal operator, A ∈ pk−QH, and B∗ is an either p-hyponormal or injective dominant or injective pk−QH operator (resp., B∗ is an either p-hyponormal or dominant or pk −QH operator), then δAB(X) = 0 =⇒ δA∗B∗(X) = 0 (resp., ...

We consider the X-ray transform in a projective space over a finite field. It is well known (after E. Bolker) that this transform is injective. We formulate an analog of I.M. Gelfand’s admissibility problem for the Radon transform, which asks for a classification of all minimal sets of lines for which the restricted Radon transform is injective. The solution involves doubly ruled quadric surfaces.

It is well known that S1 2 cannot prove the injective weak pigeonhole principle for polynomial time functions unless RSA is insecure. In this note we investigate the provability of the surjective (dual) weak pigeonhole principle in S1 2 for provably weaker function classes. §

Our dual notions “locally injective” and “locally projective” modules in Mod-R are good tools to study the relations between the singular, respectively cosingular, submodule of Hom R(M, W ) and the total Tot (M, W ). These notions have further interesting properties.

For the Auslander algebras E of self-injective Nakayama algebras, the Δ-filtrations of the submodules of indecomposable projective Emodules are determined, a class of Δ-filtered E-modules without selfextensions are constructed, and the Ringel dual of E is described. Mathematics Subject Classifications: 16G10

We classify a certain class of minimal actions of a compact Kac algebra with amenable dual on injective factors of type III. Our main technical tools are the structural analysis of type III factors and the theory of canonical extension of endomorphisms introduced by Izumi.