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We study certain dynamical systems which leave invariant an indefinite quadratic form via semigroups or evolution families of complex symmetric Hilbert space operators. In the setting of bounded operators we show that a…

Dynamical Systems · Mathematics 2020-03-09 Pham Viet Hai , Mihai Putinar

Operator spreading under unitary time evolution has attracted a lot of attention recently, as a way to probe many-body quantum chaos. While quantities such as out-of-time-ordered correlators (OTOC) do distinguish interacting from…

Strongly Correlated Electrons · Physics 2021-09-17 Javier Lopez-Piqueres , Brayden Ware , Sarang Gopalakrishnan , Romain Vasseur

In this paper we study fixed point properties for semitopological semigroup of nonexpansive mappings on a bounded closed convex subset of a Banach space. We also study a Schauder fixed point property for a semitopological semigroup of…

Functional Analysis · Mathematics 2012-07-20 A. T. -M. Lau , Yong Zhang

This article introduces an enhanced particle swarm optimizer (PSO), termed Orthogonal PSO with Mutation (OPSO-m). Initially, it proposes an orthogonal array-based learning approach to cultivate an improved initial swarm for PSO,…

Neural and Evolutionary Computing · Computer Science 2024-05-22 Indu Bala , Dikshit Chauhan , Lewis Mitchell

Non-commutative polynomial optimization (NPO) problems seek to minimize the state average of a polynomial of some operator variables, subject to polynomial constraints, over all states and operators, as well as the Hilbert spaces where…

Quantum Physics · Physics 2025-07-22 Mateus Araújo , Andrew J. P. Garner , Miguel Navascues

While many problems in machine learning focus on learning mappings between finite-dimensional spaces, scientific applications require approximating mappings between function spaces, i.e., operators. We study the problem of learning…

Machine Learning · Computer Science 2025-10-30 Adrien Weihs , Jingmin Sun , Zecheng Zhang , Hayden Schaeffer

We study the asymptotics of strongly continuous operator semigroups defined on locally convex spaces in order to develop a stability theory for solutions of evolution equations beyond Banach spaces. In the classical case, there is only…

Analysis of PDEs · Mathematics 2016-03-03 Birgit Jacob , Sven-Ake Wegner

We obtain uniqueness theorems for harmonic and subharmonic functions of a new type. They lead to new analytic extension criteria and new conditions for stability of operator semigroups in Banach spaces with Fourier type.

Complex Variables · Mathematics 2007-05-23 A. Borichev , R. Chill , Yu. Tomilov

Let $A$ be a bounded linear operator and $P$ a bounded linear projection on a Banach space $X$. We show that the operator semigroup $(e^{t(A-kP)})_{t \ge 0}$ converges to a semigroup on a subspace of $X$ as $k \to \infty$ and we compute the…

Functional Analysis · Mathematics 2016-01-27 Jochen Glück

We present a novel semiclassical framework tailored to determine the scaling dimensions of heavy neutral composite operators in conformal field theories (CFTs) which are inaccessible with other current methodologies. It utilizes the…

High Energy Physics - Theory · Physics 2026-02-03 Oleg Antipin , Jahmall Bersini , Jacob Hafjall , Giulia Muco , Francesco Sannino

We characterize the semigroups of composition operators that are strongly continuous on the mixed norm spaces $H(p,q,\alpha)$. First, we study the separable spaces $H(p,q,\alpha)$ with $q<\infty,$ that behave as the Hardy and Bergman…

Functional Analysis · Mathematics 2016-10-28 Irina Arévalo , Manuel D. Contreras , Luis Rodríguez-Piazza

The aim of this article is to study semigroups of composition operators on the BMOA-type spaces $BMOA_p$, and on their "little oh" analogues $VMOA_p$. The spaces $BMOA_p$ were introduced by R. Zhao as part of the large family of F(p,q,s)…

Functional Analysis · Mathematics 2023-07-24 Vassilis Daskalogiannis , Petros Galanopoulos

Let (M,\mu) be a sigma-finite measure space. Let (T_t) be a semigroup of positive preserving maps on (M,\mu) with standard assumptions. We prove a H_1-BMO duality theory with assumptions only on T_t. The BMO is defined as spaces of…

Classical Analysis and ODEs · Mathematics 2012-05-01 Tao Mei

Machine scheduling problems are a long-time key domain of algorithms and complexity research. A novel approach to machine scheduling problems are fixed-parameter algorithms. To stimulate this thriving research direction, we propose 15 open…

Optimization and Control · Mathematics 2018-10-02 Matthias Mnich , René van Bevern

Let S be a dense sub-semigroup of the positive real numbers, and let X be a separable, reflexive Banach space. This note contains a proof that every weakly continuous contractive semigroup of operators on X over S can be extended to a…

Functional Analysis · Mathematics 2009-03-21 Eliahu Levy , Orr Shalit

This survey describes the method of approximation of operator semigroups, based on the Chernoff theorem. We outline recent results in this domain as well as clarify relations between constructed approximations, stochastic processes,…

Functional Analysis · Mathematics 2021-03-16 Yana A. Butko

Many engineered systems, such as energy and transportation infrastructures, are networks governed by non-linear physical laws. A primary challenge for operators of these networks is to achieve optimal utilization while maintaining safety…

Optimization and Control · Mathematics 2018-03-08 Tillmann Weisser , Line Roald , Sidhant Misra

We introduce a new numerical algorithm based on semidefinite programming to efficiently compute bounds on operator dimensions, central charges, and OPE coefficients in 4D conformal and N=1 superconformal field theories. Using our algorithm,…

High Energy Physics - Theory · Physics 2014-07-31 David Poland , David Simmons-Duffin , Alessandro Vichi

Neural Operators (NOs) provide a powerful framework for computations involving physical laws that can be modelled by (integro-) partial differential equations (PDEs), directly learning maps between infinite-dimensional function spaces that…

Machine Learning · Computer Science 2025-09-18 Gianluca Fabiani , Hannes Vandecasteele , Somdatta Goswami , Constantinos Siettos , Ioannis G. Kevrekidis

In this article we survey recent progress in the algorithmic theory of matrix semigroups. The main objective in this area of study is to construct algorithms that decide various properties of finitely generated subsemigroups of an infinite…

Discrete Mathematics · Computer Science 2023-09-21 Ruiwen Dong