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Related papers: $k$-decomposability of positive maps

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The paper revisits concretely the algebraic K-theory in the light of the global program of Langlands by taking into account the new algebraic interpretation of homotopy viewed as deformation(s) of Galois representations given by…

General Mathematics · Mathematics 2010-09-15 Christian Pierre

$G$-deformability of maps into projective space is characterised by the existence of certain Lie algebra valued 1-forms. This characterisation gives a unified way to obtain well known results regarding deformability in different geometries.

Differential Geometry · Mathematics 2021-02-26 Mason Pember

We give an explicit description of the set of all factorization structures, or twisting maps, existing between the algebras k^2 and k^2, and classify the resulting algebras up to isomorphism. In the process we relate several different…

Rings and Algebras · Mathematics 2016-08-16 Javier López Peña , Gabriel Navarro

We prove that the Hilbert scheme of the plane in positive characteristic admits an invertible top differential form. This implies certain integrability properties of the symmetric powers of the plane. This allows to define a function on the…

Algebraic Geometry · Mathematics 2026-02-19 Avraham Aizenbud , Dmitry Gourevitch , David Kazhdan , Eitan Sayag

In this article we address the first part of the programme presented in \cite{Teleman_arXiv_III}, \S 2; we construct the local $K$- theory level of the index formula. Our construction is sufficiently general to encompass the algebra of…

K-Theory and Homology · Mathematics 2013-08-29 Nicolae Teleman

In this paper we consider disjoint decomposition of algebraic and non-linear partial differential systems of equations and inequations into so-called simple subsystems. We exploit Thomas decomposition ideas and develop them into a new…

Commutative Algebra · Mathematics 2015-05-19 Thomas Bächler , Vladimir Gerdt , Markus Lange-Hegermann , Daniel Robertz

Finite rank perturbations $T=N+K$ of a bounded normal operator $N$ on a separable Hilbert space are studied thanks to a natural functional model of $T$; in its turn the functional model solely relies on a perturbation matrix/ characteristic…

Functional Analysis · Mathematics 2020-08-03 Mihai Putinar , Dmitry Yakubovich

We make two observations regarding the invertibility of Keller maps. i.e., polynomial maps for which the determinant of their Jacobian matrix is identically equal to 1. In our first result, we show that if P is a n-dimensional Keller map,…

Algebraic Geometry · Mathematics 2007-05-23 Richard J. Lipton , Evangelos Markakis

A compact set has computable type if any homeomorphic copy of the set which is semicomputable is actually computable. Miller proved that finite-dimensional spheres have computable type, Iljazovi\'c and other authors established the property…

Logic · Mathematics 2023-07-10 Djamel Eddine Amir , Mathieu Hoyrup

We deform Heisenberg algebra and corresponding coalgebra by twist. We present undeformed and deformed tensor identities. Coalgebras for the generalized Poincar\'{e} algebras have been constructed. The exact universal $R$-matrix for the…

Mathematical Physics · Physics 2015-06-04 Stjepan Meljanac , Andjelo Samsarov , Rina Strajn

We classify all decompositions of $M_3(\mathbb{C})$ into a direct vector-space sum of two subalgebras such that one of the subalgebras contains the identity matrix.

Rings and Algebras · Mathematics 2022-01-25 Vsevolod Gubarev

We give a decomposition as a direct sum of indecomposable modules of several types of Specht modules in characteristic $2$. These include the Specht modules labelled by hooks, whose decomposability was considered by Murphy. Since the main…

Representation Theory · Mathematics 2023-02-01 Stephen Donkin , Haralampos Geranios

The paper studies the deformation theory of a holomorphic surjective map from a normal compact complex space to a compact Kaehler manifold and describes the component of the space of holomorphic maps, generalizing results in the projective…

Algebraic Geometry · Mathematics 2007-05-23 Jun-Muk Hwang , Thomas Peternell

For a semibounded sesquilinear form ${\mathfrak t}$ in a Hilbert space ${\mathfrak H}$ there exists a representing map $Q$ from ${\mathfrak H}$ to another Hilbert space ${\mathfrak K}$, such that ${\mathfrak t}[\varphi, \psi]-c(\varphi,…

Functional Analysis · Mathematics 2024-01-02 Seppo Hassi , Henk de Snoo

The main purpose of this paper is to present a decomposition theorem for nonnegative sesquilinear forms. The key notion is the short of a form to a linear subspace. This is a generalization of the well-known operator short defined by M. G.…

Functional Analysis · Mathematics 2014-06-26 Zoltán Sebestyén , Zsigmond Tarcsay , Tamás Titkos

We study copositive matrices which admit a decomposition into a sum of a positive semidefinite matrix and a matrix with nonnegative entries. Our main result shows that if the off-diagonal entries of a copositive matrix are nondecreasing in…

Optimization and Control · Mathematics 2026-05-18 Grigoriy Blekherman , Santanu S. Dey , Alex Dunbar , Burak Kocuk

Local versions of measurability have been around for a long time. Roughly, one splits the notion of $\mu $-completeness into pieces, and asks for a uniform ultrafilter over $\mu $ satisfying just some piece of $\mu $-completeness. Analogue…

Logic · Mathematics 2014-04-08 Paolo Lipparini

This paper revisits the problem of decomposing a positive semidefinite matrix as a sum of a matrix with a given rank plus a sparse matrix. An immediate application can be found in portfolio optimization, when the matrix to be decomposed is…

Optimization and Control · Mathematics 2021-06-16 Michel Baes , Calypso Herrera , Ariel Neufeld , Pierre Ruyssen

We will consider completely positive maps defined on tensor products of von Neumann algebras and taking values in the algebra of bounded operators on a Hilbert space and particularly certain convex subsets of the set of such maps. We show…

Quantum Physics · Physics 2014-03-21 Erkka Haapasalo , Teiko Heinosaari , Juha-Pekka Pellonpää

In the present paper, we introduce the notion of $E$-$g$-frames for a separable Hilbert spaces $\mathcal H$, where $E$ is an invertible infinite matrix mapping on the Hilbert space $\mathop\oplus\limits_{n=1}^{\infty}\mathcal H_n$. We study…

Functional Analysis · Mathematics 2024-01-10 H. Hedayatirad , T. L. Shateri