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Let K \subset L be a field extension. Given K-subspaces A,B of L, we study the subspace spanned by the product set AB = {ab | a \in A, b \in B}. We obtain some lower bounds on the dimension of this subspace and on dim B^n in terms of dim A,…

Combinatorics · Mathematics 2021-08-19 Shalom Eliahou , Cédric Lecouvey

Let $A$ be a unital $C^*$-algebra containing a closed two-sided ideal $J$ and an operator system $X$. We enlarge $X$ to an operator system $\mathcal{S}(X,J)$ in $\mathbb{M}_2(A)$, and show that in order for $\mathcal{S}(X,J)$ to be…

Operator Algebras · Mathematics 2025-09-24 Raphaël Clouâtre

Motivated by questions like: which spatial structures may be characterized by means of modal logic, what is the logic of space, how to encode in modal logic different geometric relations, topological logic provides a framework for studying…

Logic · Mathematics 2014-01-07 Tarek Sayed Ahmed

A differential algebra of finite type over a field k is a filtered algebra A, such that the associated graded algebra is finite over its center, and the center is a finitely generated k-algebra. The prototypical example is the algebra of…

Rings and Algebras · Mathematics 2007-05-23 Amnon Yekutieli , James J. Zhang

In the large rank limit, for any nonexceptional affine algebra, the graded branching multiplicities known as one-dimensional sums, are conjectured to have a simple relationship with those of type A, which are known as generalized Kostka…

Combinatorics · Mathematics 2007-05-23 Mark Shimozono

The weak operator topology closed operator algebra on $L^2(R)$ generated by the one-parameter semigroups for translation, dilation and multiplication by $exp(i\lambda x), \lambda \geq 0$, is shown to be a reflexive operator algebra, in the…

Operator Algebras · Mathematics 2015-03-06 Eleftherios Kastis , Stephen Power

In this paper we study a family of algebraic deformations of regular coadjoint orbits of compact semisimple Lie groups with the Kirillov Poisson bracket. The deformations are restrictions of deformations on the dual of the Lie algebra. We…

Quantum Algebra · Mathematics 2007-05-23 R. Fioresi , A. Levrero , M. A. Lledó

We present a solution for the classical univariate rational interpolation problem by means of (univariate) subresultants. In the case of Cauchy interpolation (interpolation without multiplicities), we give explicit formulas for the solution…

Commutative Algebra · Mathematics 2014-03-25 Carlos D'Andrea , Teresa Krick , Agnes Szanto

We give a relation between the existence of a Zariski decomposition and the behavior of the restricted volume of a big divisor on a smooth (complex) projective variety. Moreover, we give an analytic description of the restricted volume in…

Algebraic Geometry · Mathematics 2013-01-17 Shin-ichi Matsumura

Recently we constructed Mahler discrete residues for rational functions and showed they comprise a complete obstruction to the Mahler summability problem of deciding whether a given rational function $f(x)$ is of the form $g(x^p)-g(x)$ for…

Number Theory · Mathematics 2025-03-21 Carlos E. Arreche , Yi Zhang

We prove that the tensor algebra of a C*-correspondence $X$ is Dirichlet if and only if $X$ is a Hilbert bimodule. As a consequence, we point out and fix an error appearing in the proof of a famous result of Duncan. Secondly we answer a…

Operator Algebras · Mathematics 2014-04-08 Evgenios T. A. Kakariadis

We construct a weak dilation of a not necessarily unital CP-semigroup to an E-semigroup acting on the adjointable operators of a Hilbert module with a unit vector. We construct the dilation in such a way that the dilating E-semigroup has a…

Operator Algebras · Mathematics 2013-11-20 Michael Skeide

This paper is devoted to Riemann-Hilbert problems with constraints. We obtain results characterizing the existence of solutions as well as the dimension of the solution space in terms of certain indices. As an application, we show how such…

Complex Variables · Mathematics 2018-08-22 Florian Bertrand , Giuseppe Della Sala

Given a row contraction of operators on Hilbert space and a family of projections on the space which stabilize the operators, we show there is a unique minimal joint dilation to a row contraction of partial isometries which satisfy natural…

Functional Analysis · Mathematics 2007-05-23 Michael T. Jury , David W. Kribs

We construct all the possible non-relativistic, non-trivial, Galilei and Carroll k-contractions also known as k-1 p-brane contractions of the Maxwell algebra in $D+1$ space-time dimensions. $k$ has to do with the number of space-time…

High Energy Physics - Theory · Physics 2019-09-13 Andrea Barducci , Roberto Casalbuoni , Joaquim Gomis

By applying inter-universal Teichm\"uller theory and its slight modification over the rational number field, we prove new Diophantine results towards effective abc inequalities and the generalized Fermat equations. For coprime integers $a,…

Number Theory · Mathematics 2025-03-20 Zhong-Peng Zhou

We discuss a discrete analogue of the Dirac-K\"{a}hler equation in which chiral properties of the continual counterpart are captured. We pay special attention to a discrete Hodge star operator. To build one a combinatorial construction of…

Mathematical Physics · Physics 2016-09-16 Volodymyr Sushch

We show that if $\lambda_1,\ldots,\lambda_k$ are algebraic numbers, then $$|A+\lambda_1\cdot A+\dots+\lambda_k\cdot A|\geq H(\lambda_1,\ldots,\lambda_k)|A|-o(|A|)$$ for all finite subsets $A$ of $\mathbb{C}$, where…

Combinatorics · Mathematics 2025-08-27 David Conlon , Jeck Lim

We prove weighted analytic regularity of solutions to the Dirichlet problem for the integral fractional Laplacian in polygons with analytic right-hand side. We localize the problem through the Caffarelli-Silvestre extension and study the…

Analysis of PDEs · Mathematics 2023-11-27 Markus Faustmann , Carlo Marcati , Jens Markus Melenk , Christoph Schwab

Normal modal logics extending the logic K4.3 of linear transitive frames are known to lack the Craig interpolation property, except some logics of bounded depth such as S5. We turn this `negative' fact into a research question and pursue a…

Logic · Mathematics 2025-08-14 Agi Kurucz , Frank Wolter , Michael Zakharyaschev