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In this note the smooth (i.e. with open stabilizers) linear and {\sl semilinear} representations of certain permutation groups (such as infinite symmetric group or automorphism group of an infinite-dimensional vector space over a finite…

Representation Theory · Mathematics 2015-08-18 M. Rovinsky

In the study of locally convex quasi *-algebras an important role is played by representable linear functionals; i.e., functionals which allow a GNS-construction. This paper is mainly devoted to the study of the continuity of representable…

Functional Analysis · Mathematics 2017-06-14 Maria Stella Adamo , Camillo Trapani

We study maximal regularity with respect to continuous functions for strongly continuous semigroups on locally convex spaces as well as its relation to the notion of admissible operators. This extends several results for classical strongly…

Functional Analysis · Mathematics 2025-10-22 Karsten Kruse , Felix L. Schwenninger

We construct a locally finite graph and a bounded geometry metric space which do not admit a quasi-isometric embedding into any uniformly convex Banach space. Connections with the geometry of $c_0$ and superreflexivity are discussed.

Metric Geometry · Mathematics 2015-01-29 Piotr W. Nowak

We prove that a Banach space X is not super-reflexive if and only if the hyperbolic infinite tree embeds metrically into X. We improve one implication of J.Bourgain's result who gave a metrical characterization of super-reflexivity in…

Functional Analysis · Mathematics 2017-09-27 Florent Baudier

The inclusion equations of the type $f \in T ( x)$ where $T: X \to 2^{X^{\ast}}$ is a maximal monotone map, are extensively studied in nonlinear analysis. In this paper, we present a new construction of the degree of maximal monotone maps…

Analysis of PDEs · Mathematics 2019-04-03 Mohammad Niksirat

We show that any bounded operator $T$ on a separable, reflexive, infinite-dimensional Banach space $X$ admits a rank one perturbation which has an invariant subspace of infinite dimension and codimension. In the non-reflexive spaces, we…

Functional Analysis · Mathematics 2012-08-30 Alexey I. Popov , Adi Tcaciuc

Let $ H $ be a compact subgroup of a locally compact group $G$. In this paper we define a convolution on $ M(G/H) $, the space of all complex bounded Radon measures on the homogeneous space G/H. Then we prove that the measure space $ M(G/H,…

Representation Theory · Mathematics 2017-02-22 T. Derikvand , R. A. Kamyabi-Gol , M. Janfada

Diffeomorphism groups $G$ of manifolds $M$ on locally $\bf F$-convex spaces over non-Archimedean fields $\bf F$ are investigated. It is shown that their structure has many differences with the diffeomorphism groups of real and complex…

Group Theory · Mathematics 2007-05-23 S. V. Ludkovsky

We prove that the categories of smooth and analytic unitary representations of Banach--Lie supergroups are well-behaved under restriction functors, in the sense that the restriction of a representation to an integral subsupergroup is…

Representation Theory · Mathematics 2011-07-07 Stephane Merigon , Karl-Hermann Neeb , Hadi Salmasian

A group $\Gamma$ is said to be uniformly HS stable if any map $\varphi : \Gamma \to U(n)$ that is almost a unitary representation (w.r.t. the Hilbert Schmidt norm) is close to a genuine unitary representation of the same dimension. We…

Group Theory · Mathematics 2023-01-31 Danil Akhtiamov , Alon Dogon

Let $\mathcal A$ be a semisimple commutative Banach algebra. It is shown that either $\mathcal A$ has exactly one uniform norm or it admits uncountably many uniform norms. Further, it is shown that there always exists a largest closed…

Functional Analysis · Mathematics 2026-05-19 Jekwin J. Dabhi , Prakash A. Dabhi

We consider the action of finitely truncated singular integral operators on functions taking values in a Banach space. Such operators are bounded for any Banach space, but we show a quantitative improvement over the trivial bound in any…

Functional Analysis · Mathematics 2023-10-16 Tuomas Hytönen

A group G is representable in a Banach space X if G is isomorphic to the group of isometries on X in some equivalent norm. We prove that a countable group G is representable in a separable real Banach space X in several general cases,…

Functional Analysis · Mathematics 2007-07-30 Valentin Ferenczi , Eloi Medina Galego

We investigate the combinatorial structure of unrefinable partitions through their correspondence with numerical sets and Young diagrams. Building on the bijection introduced by Keith and Nath, we apply a general geometric criterion that…

Combinatorics · Mathematics 2026-02-03 Riccardo Aragona , Roberto Civino , Lorenzo Campioni

Let $A$ be a unital commutative Banach algebra with maximal ideal space $X.$ We determine the rational H-type of the group $GL_n (A)$ of invertible n by n matrices with coefficients in A, in terms of the rational cohomology of $X.$ We also…

Algebraic Topology · Mathematics 2007-05-23 Gregory Lupton , N. Christopher Phillips , Claude L. Schochet , Samuel B. Smith

We explore extreme contractions between finite-dimensional polygonal Banach spaces, from the point of view of attainment of norm of a linear operator. We prove that if $ X $ is an $ n- $dimensional polygonal Banach space and $ Y $ is any…

Functional Analysis · Mathematics 2024-08-13 Debmalya Sain , Anubhab Ray , Kallol Paul

Compact-group representations on Banach spaces are known to be norm-continuous precisely when they have finite spectra. For a quantum group with continuous-function algebra $\mathcal{C}(\mathbb{G})$ norm continuity can be cast analogously…

Operator Algebras · Mathematics 2026-03-27 Alexandru Chirvasitu

In a recent paper of Benson and Symonds, a new invariant was introduced for modular representations of a finite group. An interpretation was given as a spectral radius with respect to a Banach algebra completion of the representation ring.…

Representation Theory · Mathematics 2022-05-03 David Benson

This paper exemplifies that saturation is an indispensable structure on measure spaces to obtain the existence and characterization of solutions to nonconvex variational problems with integral constraints in Banach spaces and their dual…

Optimization and Control · Mathematics 2019-09-24 Nobusumi Sagara