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A structure M is pregeometric if the algebraic closure is a pregeometry in all M' elementarily equivalent to M. We define a generalisation: structures with an existential matroid. The main examples are superstable groups of U-rank a power…

Logic · Mathematics 2011-04-12 Antongiulio Fornasiero

We study rank-three matroids, known as point-line configurations, and their associated matroid varieties, defined as the Zariski closures of their realization spaces. Our focus is on determining finite generating sets of defining equations…

Combinatorics · Mathematics 2025-06-10 Emiliano Liwski , Fatemeh Mohammadi , Lisa Vandebrouck

Following a previous work with Boudi, we continue to investigate Bernstein algebras satisfying chain conditions. First, it is shown that a Bernstein algebra $(A, \omega)$ with ascending or descending chain condition on subalgebras is…

Rings and Algebras · Mathematics 2018-12-27 Fouad Zitan

The joint spectral radius of a finite set of real $d \times d$ matrices is defined to be the maximum possible exponential rate of growth of long products of matrices drawn from that set. A set of matrices is said to have the…

Optimization and Control · Mathematics 2012-01-31 Kevin G. Hare , Ian D. Morris , Nikita Sidorov , Jacques Theys

The strong global dimension of a ring is the supremum of the length of perfect complexes that are indecomposable in the derived category. In this note we characterize the noetherian commutative rings that have finite strong global…

Commutative Algebra · Mathematics 2013-07-17 Ragnar-Olaf Buchweitz , Hubert Flenner

Let $A$ be a commutative Noetherian ring, and let $R = A[X]$ be the polynomial ring in an infinite collection $X$ of indeterminates over $A$. Let ${\mathfrak S}_{X}$ be the group of permutations of $X$. The group ${\mathfrak S}_{X}$ acts on…

Commutative Algebra · Mathematics 2007-05-23 Matthias Aschenbrenner , Christopher J. Hillar

In 2016 Ananyan and Hochster proved Stillman's conjecture by showing the existence of a uniform upper bound on the length of an $R_\eta$-sequence containing fixed $n$ forms of degree at most $d$ in polynomial rings over a field. This result…

Commutative Algebra · Mathematics 2026-05-28 Giulio Caviglia , Yihui Liang , Cheng Meng

We introduce the concept of strong persistence and show that it implies persistence regarding the associated prime ideals of the powers of an ideal. We also show that strong persistence is equivalent to a condition on power of ideals…

Commutative Algebra · Mathematics 2012-09-04 Jürgen Herzog , Ayesha Asloob Qureshi

In this two-part paper we prove an existence result for affine buildings arising from exceptional algebraic reductive groups. Combined with earlier results on classical groups, this gives a complete and positive answer to the conjecture…

Metric Geometry · Mathematics 2012-10-24 Bernhard Mühlherr , Koen Struyve , Hendrik Van Maldeghem

We show that an adjoint of a loopless matroid is connected if and only if it itself is connected. Our first goal is to study the adjoint of modular matroids. We prove that a modular matroid has only one adjoint (up to isomorphism) which can…

Combinatorics · Mathematics 2023-04-18 Houshan Fu , Chunming Tang , Suijie Wang

The Kawaguchi-Silverman conjecture relates two different invariants of a surjective endomorphism, the dynamical and arithmetic degrees. As the Kawaguchi-Silverman conjecture is only meaningful when a morphism has a Zariski dense orbit, it…

Algebraic Geometry · Mathematics 2022-12-06 Brett Nasserden

A well-known theorem of J.E. Hutchinson states that if an iterated function system consists of similarity transformations and satisfies the open set condition then its attractor supports a self-similar measure with Hausdorff dimension equal…

Dynamical Systems · Mathematics 2021-06-22 Ian D. Morris , Cagri Sert

The nonnegative Grassmannian is a cell complex with rich geometric, algebraic, and combinatorial structures. Its study involves interesting combinatorial objects, such as positroids and plabic graphs. Remarkably, the same combinatorial…

Combinatorics · Mathematics 2018-06-15 Alexander Postnikov

Given a two-sided noetherian ring $A$ with a dualizing complex, we show that the big finitistic dimension of $A$ is finite if and only if every bounded below Gorenstein-projective-acyclic cochain complex of Gorenstein-projective $A$-modules…

Rings and Algebras · Mathematics 2023-10-10 Liran Shaul

In this article first we prove that a special case of the order ideal conjecture, originating from the work of Evans and Griffith in equicharacteristic, implies the monomial conjecture due to M. Hochster. We derive a necessary and…

Commutative Algebra · Mathematics 2013-05-07 S. P. Dutta

We construct families of rational functions $f \colon \bP^1_k \to \bP^1_k$ of degree $d \geq 2$ over a perfect field $k$ whose associated fixed-point processes fail to be martingales. Conversely, for any normal variety $X \subset…

Number Theory · Mathematics 2026-04-09 Jianfei He , Zheng Zhu

The lowest representatives of the Form Factors relative to the trace operators of N=1 Super Sinh-Gordon Model are exactly calculated. The novelty of their determination consists in solving a coupled set of unitarity and crossing equations.…

High Energy Physics - Theory · Physics 2009-10-31 G. Mussardo

We discuss an extension of the almost Hadamard matrix formalism, to the case of complex matrices. Quite surprisingly, the situation here is very different from the one in the real case, and our conjectural conclusion is that there should be…

Combinatorics · Mathematics 2017-05-15 Teodor Banica , Ion Nechita

Let $\Gamma$ be a discrete group. Following Linnell and Schick one can define a continuous ring $c(\Gamma)$ associated with $\Gamma$. They proved that if the Atiyah Conjecture holds for a torsion-free group $\Gamma$, then $c(\Gamma)$ is a…

Rings and Algebras · Mathematics 2014-02-25 Gabor Elek

We construct a family of independent sets for finite, atomic, and graded lattices, extending the well-known cryptomorphism between geometric lattices and matroids. This construction leads to an embedding theorem into geometric lattices that…

Combinatorics · Mathematics 2026-01-08 Or Raz