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Generalizing the notion of continuous Hilbert space representations of compact topological groups we define unitary continuous correpresentations of $C^*$-completions of compact quantum group Hopf algebras on arbitrary Hilbert spaces. It is…

High Energy Physics - Theory · Physics 2008-02-03 Bernhard Drabant , Wolfgang Weich

We construct projective unitary representations of the smooth Deligne cohomology group of a compact oriented Riemannian manifold of dimension 4k+1, generalizing positive energy representations of the loop group of the circle. We also…

Representation Theory · Mathematics 2007-05-23 Kiyonori Gomi

Suppose $G$ is a real reductive group. The determination of the irreducible unitary representations of $G$ is one of the major unsolved problem in representation theory. There is evidence to suggest that every irreducible unitary…

Representation Theory · Mathematics 2019-10-08 Lucas Mason-Brown

We extend the definition of conical representations for Riemannian symmetric spaces to a certain class of infinite-dimensional Riemannian symmetric spaces. Using an infinite-dimensional version of Weyl's Unitary Trick, there is a…

Representation Theory · Mathematics 2015-11-24 Matthew Dawson , Gestur Olafsson

Let $G$ and $T$ be topological groups, $\alpha : T \to \Aut(G)$ a homomorphism defining a continuous action of $T$ on $G$ and $G^\sharp := G \rtimes_\alpha T$ the corresponding semidirect product group. In this paper we address several…

Representation Theory · Mathematics 2012-08-14 Karl-Hermann Neeb

In this note we show that the representation of the additive group of the Hilbert space $L^2([0,1],\R)$ on $L^2([0,1],\C)$ given by the multiplication operators $\pi(f) := e^{if}$ is continuous but its space of smooth vectors is trivial.…

Representation Theory · Mathematics 2008-11-27 Daniel Beltita , Karl-Hermann Neeb

We find the irreducible decomposition of the Weil representation of the unitary group $\mathrm{U}_{2n}(A)$, where $A$ is a ramified quadratic extension of a finite, commutative, local, principal ideal ring $R$ and the nilpotency degree of…

Representation Theory · Mathematics 2018-05-08 Allen Herman , Momuita Shau , Fernando Szechtman

We show that in the presence of suitable commutator estimates, a projective unitary representation of the Lie algebra of a connected and simply connected Lie group G exponentiates to G. Our proof does not assume G to be finite--dimensional…

Representation Theory · Mathematics 2007-05-23 Valerio Toledano-Laredo

The corepresentation theory of continuous groups is presented without the assumption that the subgroup $G$ of the group with antilinear operations is unitary. The formulas of the corepresentation theory with unitary groups $G$ can be…

Mathematical Physics · Physics 2009-06-01 J Kocinski , M Wierzbicki

Numerous Lie supergroups do not admit superunitary representations except the trivial one, e.g., Heisenberg and orthosymplectic supergroups in mixed signature. To avoid this situation, we introduce in this paper a broader definition of…

Representation Theory · Mathematics 2017-09-05 Axel de Goursac , Jean-Philippe Michel

We realize all irreducible unitary representations of the group $\mathrm{SO}_0(n+1,1)$ on explicit Hilbert spaces of vector-valued $L^2$-functions on $\mathbb{R}^n\setminus\{0\}$. The key ingredient in our construction is an explicit…

Representation Theory · Mathematics 2024-06-18 Christian Arends , Frederik Bang-Jensen , Jan Frahm

We consider smooth representations of the unit group $G = \mathcal{A}^{\times}$ of a finite-dimensional split basic algebra $\mathcal{A}$ over a non-Archimedean local field. In particular, we prove a version of Gutkin's conjecture, namely,…

Representation Theory · Mathematics 2019-11-01 Carlos A. M. André , João Dias

The automorphism group of a regular locally finite tree is shown to admit irreducible Banach representations that are not admissible. The dense subspace of smooth vectors contains no algebraically irreducible component.

Group Theory · Mathematics 2026-03-18 Nicolas Monod

It is shown that each linear operator on a separable Hilbert space which generates a finite type I von Neumann algebra has, up to unitary equivalence, a unique representation as a direct integral of inflations of mutually unitary…

Functional Analysis · Mathematics 2017-05-26 Piotr Niemiec

The main result of this article is an application of the theory of invariant convex cones of Lie algebras to the study of unitary representations of Lie supergroups. It also includes an exposition of recent results of the second author on…

Representation Theory · Mathematics 2010-12-14 Karl-Hermann Neeb , Hadi Salmasian

We obtain a complete classification of the continuous unitary representations of oligomorphic permutation groups (those include the infinite permutation group $S_\infty$, the automorphism group of the countable dense linear order, the…

Group Theory · Mathematics 2012-05-21 Todor Tsankov

By a theorem of D. Wigner, an irreducible unitary representation with non-zero $(\frak{g},K)$-cohomology has trivial infinitesimal character, and hence up to unitary equivalence, these are finite in number. We have determined the number of…

Representation Theory · Mathematics 2023-09-25 Ankita Pal , Pampa Paul

Let v be the right regular representation of a compact quantum group G. Then (S.L.Woronowicz, "Compact quantum groups") v contains all irreducible representations of G and each irreducible representation enters v with the multiplicity equal…

Operator Algebras · Mathematics 2007-05-23 Raluca Dumitru

In this manuscript, we give a classification of all irreducible, unitary representations of complex spin groups.

Representation Theory · Mathematics 2024-04-05 Kayue Daniel Wong , Hongfeng Zhang

Let $G$ be a compact and connected Lie group and $PU(\mathcal H)$ be the group of projective unitary operators on a separable Hilbert space $\mathcal H$ endowed with the strong operator topology. We study the space $hom_{st}(G, PU(\mathcal…

Algebraic Topology · Mathematics 2021-03-08 Jesus Espinoza , Bernardo Uribe