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We develop foundational aspects of stability theory in affine logic. On the one hand, we prove appropriate affine versions of many classical results, including definability of types, existence of non-forking extensions, and other…

Logic · Mathematics 2026-03-11 Itaï Ben Yaacov , Tomás Ibarlucía

We study the general and connected stable ranks for C*-algebras. We estimate these ranks for pullbacks of C*-algebras, and for tensor products by commutative C*-algebras. Finally, we apply these results to determine these ranks for certain…

Operator Algebras · Mathematics 2018-06-26 Prahlad Vaidyanathan

Let G be a finitely generated, torsion-free, two-step nilpotent group. Let C^*(G) be the universal C^*-algebra of G. We show that acsr(C^*(G)) = acsr(C((\hat{G})_1)), where for a unital C^*-algebra A, acsr(A) is the absolute connected…

Operator Algebras · Mathematics 2007-05-23 Ping Wong Ng , Takahiro Sudo

The aim of this paper is to study foliations that remain invariant by parallel transports along the integral curves of vector fields of another foliations. According to this idea, we define a new concept of stability between foliations. A…

General Relativity and Quantum Cosmology · Physics 2009-11-11 V. J. Bolós

Tensors, or multi-linear forms, are important objects in a variety of areas from analytics, to combinatorics, to computational complexity theory. Notions of tensor rank aim to quantify the "complexity" of these forms, and are thus also…

Computational Complexity · Computer Science 2023-06-16 Mandar Juvekar , Arian Nadjimzadah

A tensor defined over a finite field $\mathbb{F}$ has low analytic rank if the distribution of its values differs significantly from the uniform distribution. An order $d$ tensor has partition rank 1 if it can be written as a product of two…

Combinatorics · Mathematics 2018-10-01 Oliver Janzer

We show that every separable simple tracially approximately divisible $C^*$-algebra has strict comparison, is either purely infinite, or has stable rank one. As a consequence, we show that every (non-unital) finite simple ${\cal Z}$-stable…

Operator Algebras · Mathematics 2021-09-07 Xuanlong Fu , Kang Li , Huaxin Lin

The main contribution of this note is to establish a framework to extend results of tensor functions over specific field to general field. As a consequence of this framework, we extend the existing work to more general settings: \emph{(1)}…

Commutative Algebra · Mathematics 2026-03-11 Qiyuan Chen

We establish a general result about extending a right invertible row over a Banach algebra to an invertible matrix. This is applied to the computation of right topological stable rank of a split exact sequence. We also introduce a…

Operator Algebras · Mathematics 2014-02-26 Kenneth R. Davidson , You Qing Ji

Notions of rank abound in the literature on tensor decomposition. We prove that strength, recently introduced for homogeneous polynomials by Ananyan-Hochster in their proof of Stillman's conjecture and generalised here to other tensors, is…

Algebraic Geometry · Mathematics 2019-10-15 Arthur Bik , Jan Draisma , Rob H. Eggermont

We study the structure and compute the stable rank of C*-algebras of finite higher-rank graphs. We completely determine the stable rank of the C*-algebra when the k-graph either contains no cycle with an entrance, or is cofinal. We also…

Operator Algebras · Mathematics 2021-09-08 David Pask , Adam Sierakowski , Aidan Sims

In this paper we study the preservation of strong stability of strongly continuous semigroups on Hilbert spaces. In particular, we study a situation where the generator of the semigroup has a finite number of spectral points on the…

Functional Analysis · Mathematics 2014-11-10 Lassi Paunonen

The article is concerned with the problem of the additivity of the tensor rank. That is for two independent tensors we study when the rank of their direct sum is equal to the sum of their individual ranks. The statement saying that…

Algebraic Geometry · Mathematics 2022-09-23 Filip Rupniewski

In this paper, we give a survey of the known results concerning the tensor rank of the multiplication in finite fields and we establish new asymptotical and not asymptotical upper bounds about it.

Algebraic Geometry · Mathematics 2011-07-13 Stéphane Ballet , Jean Chaumine , Julia Pieltant , Robert Rolland

Asymptotic tensor rank is notoriously difficult to determine. Indeed, determining its value for the $2\times 2$ matrix multiplication tensor would determine the matrix multiplication exponent, a long-standing open problem. On the other…

Computational Complexity · Computer Science 2024-11-26 Matthias Christandl , Koen Hoeberechts , Harold Nieuwboer , Péter Vrana , Jeroen Zuiddam

A tensor defined over a finite field $\mathbb{F}$ has low analytic rank if the distribution of its values differs significantly from the uniform distribution. An order $d$ tensor has partition rank 1 if it can be written as a product of two…

Combinatorics · Mathematics 2020-05-19 Oliver Janzer

We show that three notions of rank for matrices of multilinear forms are equivalent. This result generalizes a classical result of Flanders, corrects a minor hole in work of Fortin and Reutenauer, answers a question of Lampert on the…

Combinatorics · Mathematics 2026-03-12 Guy Moshkovitz , Daniel G. Zhu

In this paper we study various versions of extension complexity for polygons through the study of factorization ranks of their slack matrices. In particular, we develop a new asymptotic lower bound for their nonnegative rank, shortening the…

Combinatorics · Mathematics 2016-11-29 António Pedro Goucha , João Gouveia , Pedro M. Silva

We consider slope stability of the canonical extension of the tangent bundle by the trivial line bundle and with the extension class c_1(T_X) on Picard-rank-1 Fano varieties. In cases where the index divides the dimension or the dimension…

Algebraic Geometry · Mathematics 2023-05-02 Kuang-Yu Wu

We prove a lower bound on the rank of tensors constructed from families of linear maps that `expand' the dimension of every subspace. Such families, called {\em dimension expanders} have been studied for many years with several known…

Combinatorics · Mathematics 2025-12-10 Zeev Dvir