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We introduce a notion of "weak model category" which is a weakening of the notion of Quillen model category, still sufficient to define a homotopy category, Quillen adjunctions, Quillen equivalences and most of the usual construction of…

Category Theory · Mathematics 2020-05-12 Simon Henry

In this paper, we define weakly coherent rings, and examine the transfer of these rings to homomorphic image, trivial ring extension, localization, and direct product. These results provide examples of weakly coherent rings that are not…

Commutative Algebra · Mathematics 2010-03-17 Chahrazade Bakkari , Najib Mahdou

For given non-consistent initial conditions, we study the stability of a class of generalised linear systems of difference equations with constant coefficients and taking into account that the leading coefficient can be a singular matrix.…

Dynamical Systems · Mathematics 2016-12-14 Nicholas Apostolopoulos , Fernando Ortega , Grigoris Kalogeropoulos

An experimental method has been developed to locate unstable equilibria of nonlinear structures quasi-statically. The technique involves loading a structure by application of either a force or a displacement at a main actuation point, while…

Applied Physics · Physics 2018-06-27 R. M. Neville , R. M. J. Groh , A. Pirrera , M. Schenk

For a real or complex one-dimensional map satisfying a weak hyperbolicity assumption, we study the existence and statistical properties of physical measures, with respect to geometric reference measures. We also study geometric properties…

Dynamical Systems · Mathematics 2014-06-12 Juan Rivera-Letelier , Weixiao Shen

Secondary homological stability is a recently discovered stability pattern for the homology of a sequence of spaces exhibiting homological stability in a range where homological stability does not hold. We prove secondary homological…

Algebraic Topology · Mathematics 2023-07-04 Zachary Himes

We prove a stability theorem for families of holomorphically-parallelizable manifolds in the category of Hermitian manifolds.

Complex Variables · Mathematics 2015-07-13 Daniele Angella , Adriano Tomassini

Ordered pairs of proper, non-empty real projective conics can be classified modulo rigid isotopy and ambient isotopy. We characterize the classes by equations, inequations and inequalities in the coefficients of the quadratic forms defining…

Commutative Algebra · Mathematics 2025-02-18 Emmanuel Briand

In this paper we study structurally stable homoclinic classes. In a natural way, the structural stability for an individual homoclinic class is defined through the continuation of periodic points. Since the homoclinic classes is not…

Dynamical Systems · Mathematics 2014-10-20 Xiao Wen

A theorem is proved to verify incremental stability of a feedback system via a homotopy from a known incrementally stable system. A first corollary of that result is that incremental stability may be verified by separation of Scaled…

Optimization and Control · Mathematics 2024-12-03 Thomas Chaffey , Andrey Kharitenko , Fulvio Forni , Rodolphe Sepulchre

Extending the thoroughly studied theory of group stability, we study Ulam stability type problems for associative and Lie algebras; namely, we investigate obstacles to rank-approximation of almost solutions by exact solutions for systems of…

Rings and Algebras · Mathematics 2025-07-11 Tomer Bauer , Guy Blachar , Be'eri Greenfeld

Robustness of linear systems with constant coefficients is considered. There exist methods and tools for analyzing the stability of systems with random or deterministic uncertainties. At the same time, there are no approaches for the…

Optimization and Control · Mathematics 2020-12-08 Andrey Tremba

Weak values are usually associated with weak measurements of an observable on a pre- and post-selected ensemble. We show that more generally, weak values are proportional to the correlation between two pointers in a successive measurement.…

Quantum Physics · Physics 2009-08-03 Lars M. Johansen , Pier A. Mello

We show cocycle stability for linear maps with a weak irreducibility condition and their jointly integrable perturbations.

Dynamical Systems · Mathematics 2023-05-03 Ignacio Correa

A general force-perturbation-based criterion for solid instability is proposed, which can predict instability including crease without priori knowledge of instability configuration. The crease instability is analyzed in detail, we found…

Soft Condensed Matter · Physics 2020-01-01 Pengfei Yang , Yaopeng Fang , Yanan Yuan , Shun Meng , Haroon Imtiaz , Bin Liu , Huajian Gao

A C*-algebra is said to be K-stable if its nonstable K-groups are naturally isomorphic to the usual K-theory groups. We study continuous $C(X)$-algebras, each of whose fibers are K-stable. We show that such an algebra is itself K-stable…

Operator Algebras · Mathematics 2020-05-11 Apurva Seth , Prahlad Vaidyanathan

The consistency problem for a class of algebraic structures asks for an algorithm to decide for any given conjunction of equations whether it admits a non-trivial satisfying assignment within some member of the class. By Adyan (1955) and…

Logic · Mathematics 2016-07-13 Christian Herrmann , Yasuyuki Tsukamoto , Martin Ziegler

Fix a weakly minimal (i.e., superstable $U$-rank $1$) structure $\mathcal{M}$. Let $\mathcal{M}^*$ be an expansion by constants for an elementary substructure, and let $A$ be an arbitrary subset of the universe $M$. We show that all…

Logic · Mathematics 2022-03-08 Gabriel Conant , Michael C. Laskowski

We develop a general framework (multidimensional asymptotic classes, or m.a.c.s) for handling classes of finite first order structures with a strong uniformity condition on cardinalities of definable sets: The condition asserts that…

Logic · Mathematics 2024-08-02 Sylvy Anscombe , Dugald Macpherson , Charles Steinhorn , Daniel Wolf

This paper deals with classes of (de)stabilizing switching signals for switched systems. Most of the available conditions for stability of switched systems are sufficient in nature, and consequently, their violation does not conclude…

Systems and Control · Electrical Eng. & Systems 2020-05-17 Atreyee Kundu