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We study $\varepsilon$-stability in continuous logic. We first consider stability in a model, where we obtain a definability of types result with a better approximation than that in the literature. We also prove forking symmetry for…

Logic · Mathematics 2024-11-08 Nicolas Chavarria

Motivated by the applications, a class of optimal control problems is investigated, where the goal is to influence the behavior of a given population through another controlled one interacting with the first. Diffusive terms accounting for…

Optimization and Control · Mathematics 2023-03-10 Stefano Almi , Marco Morandotti , Francesco Solombrino

It is a well-known empirical phenomenon that natural axiomatic theories are pre-well-ordered by consistency strength. Without a precise mathematical definition of "natural," it is unclear how to study this phenomenon mathematically. We will…

Logic · Mathematics 2026-03-04 James Walsh

We provide a new approach to stable ergodicity of systems with dominated splittings, based on a geometrical analysis of global stable and unstable manifolds of hyperbolic points. Our method suggests that the lack of uniform size of Pesin's…

Dynamical Systems · Mathematics 2008-12-16 Martin Andersson

In finite problems comprising objects, situations, and an object- and situation-contingent payoff function, we study the comparative statics of the set of undominated objects, meaning those for which there exists no mixture over objects…

Theoretical Economics · Economics 2026-01-23 Gregorio Curello , Ludvig Sinander , Mark Whitmeyer

The problem of homological stability helps us to catch the structure of group homology. We calculate homological stability of special orthogonal groups, and we also calculate the stability of orthogonal groups with determinant-twisted…

K-Theory and Homology · Mathematics 2015-11-04 Masayuki Nakada

Geometrical stability theory is a powerful set of model-theoretic tools that can lead to structural results on models of a simple first-order theory. Typical results offer a characterization of the groups definable in a model of the theory.…

Logic · Mathematics 2007-05-23 Steven Buechler , Olivier Lessmann

A dependent theory is a (first order complete theory) T which does not have the independence property. A main result here is: if we expand a model of T by the traces on it of sets definable in a bigger model then we preserve its being…

Logic · Mathematics 2013-02-20 Saharon Shelah

Symmetry properties of the evolution equation and the state to be controlled are shown to determine the basic features of the linear control of unstable orbits. In particular, the selection of control parameters and their minimal number are…

chao-dyn · Physics 2009-10-30 R. O. Grigoriev , M. C. Cross

In the present work we suggest a general covariant theory which can be used to study the stability of any physical system treated geometrically. Stability conditions are connected to the magnitude of the deviation vector. This theory is a…

General Relativity and Quantum Cosmology · Physics 2016-11-15 M. I. Wanas , M. A. Bakry

In this survey we recall basic notions of disintegration of measures and entropy along unstable laminations. We review some roles of unstable entropy in smooth ergodic theory including the so-called invariance principle, Margulis…

Dynamical Systems · Mathematics 2021-08-11 Ali Tahzibi

This Ph.D. thesis is divided in two parts. The first one concerns the equilibrium properties of glassy systems. Some aspects of the phenomenology of glasses and of theories attempting to describe them are reviewed in chapter 1. A study of…

Disordered Systems and Neural Networks · Physics 2007-05-23 F. Zamponi

In a recent paper by two of the authors, the concepts of upwards and downwards $\epsilon$-movability were introduced, mainly as a technical tool for studying dynamical percolation of interacting particle systems. In this paper, we further…

Probability · Mathematics 2007-05-23 Erik I. Broman , Olle Haggstrom , Jeffrey E. Steif

We consider the minimum weight and smallest weight minimum-size dominating set problems in vertex-weighted graphs and networks. The latter problem is a two-objective optimization problem, which is different from the classic minimum weight…

Combinatorics · Mathematics 2024-01-23 Lukas Dijkstra , Andrei Gagarin , Vadim Zverovich

In this paper we define unstable topological entropy for any subsets (not necessarily compact or invariant) in partially hyperbolic systems as a Carath\'{e}odory dimension characteristic, motivated by the work of Bowen and Pesin etc. We…

Dynamical Systems · Mathematics 2018-11-12 Xueting Tian , Weisheng Wu

In a previous paper we developed the notions of th-independence and \th-ranks which define a geometric independence relation in a class of theories which we called ``rosy''. We proved that rosy theories include simple and o-minimal theories…

Logic · Mathematics 2007-05-23 Alf Onshuus

We present a unifying framework of residual domination for (expansions of) henselian valued fields of equicharacteristic zero, encompassing some valued fields with operators. We show that the class of residually dominated types coincides…

We study links between first-order formulas and arbitrary properties for families of theories, classes of structures and their isomorphism types. Possibilities for ranks and degrees for formulas and theories with respect to given properties…

Logic · Mathematics 2021-04-02 Sergey V. Sudoplatov

We study the problem of half-domination sets of vertices in vertex transitive infinite graphs generated by regular or semi-regular tessellations of the plane. In some cases, the results obtained are sharp and in the rest, we show upper…

Combinatorics · Mathematics 2015-03-13 Eugen J. Ionascu

A trichotomy theorem for countable, stable, unsuperstable theories is offered. We develop the notion of a `regular ideal' of formulas and study types that are minimal with respect to such an ideal.

Logic · Mathematics 2007-11-21 Michael C. Laskowski , Saharon Shelah