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Given a compact subgroup K of the orthogonal group acting on the Euclidean space Rn, Gerald Schwarz proved that every smooth K-invariant function on Rn can be expressed as a smooth function of a generating set of $K$-invariant polynomials…

Functional Analysis · Mathematics 2025-10-14 Rocío Díaz Martín , Linda Saal

Combinatorial $t$-designs have been an interesting topic in combinatorics for decades. It was recently reported that the image sets of a fixed size of certain special polynomials may constitute a $t$-design. Till now only a small amount of…

Information Theory · Computer Science 2019-07-16 Can Xiang , Xin Ling , Qi Wang

We give a completely explicit formula for all harmonic maps of finite uniton number from a Riemann surface to the unitary group U(n) in any dimension, and so all harmonic maps from the 2-sphere, in terms of freely chosen meromorphic…

Differential Geometry · Mathematics 2009-09-01 Maria João Ferreira , Bruno A. Simões , John C. Wood

A unitary t-design is a set of unitaries that is "evenly distributed" in the sense that the average of any t-th order polynomial over the design equals the average over the entire unitary group. In various fields -- e.g. quantum information…

Quantum Physics · Physics 2016-09-28 Huangjun Zhu , Richard Kueng , Markus Grassl , David Gross

If a (weighted) spherical design is defined as an integration (cubature) rule for a unitarily invariant space P of polynomials (on the sphere), then any unitary image of it is also such a spherical design. It therefore follows that such…

General Mathematics · Mathematics 2025-11-12 Shayne Waldron

Let G be a locally compact group and let K be a compact subgroup of Aut(G), the group of automorphisms of G. The pair $(G, K )$ is a Gelfand pair if the algebra $L^{1}_{K}(G)$ of K-invariant integrable functions on G is commutative under…

Classical Analysis and ODEs · Mathematics 2024-01-17 Cornelie Mitcha Malanda

This article is devoted to the investigation of semidirect products of groups of loops and groups of diffeomorphisms of finite and infinte dimensional real, complex and quaternion manifolds. Necessary statements about quaternion manifolds…

Algebraic Geometry · Mathematics 2010-03-16 S. V. Ludkovsky

For an infinite dimensional Lie group $G$ modelled on a locally convex Lie algebra $\mathfrak{g}$, we prove that every smooth projective unitary representation of $G$ corresponds to a smooth linear unitary representation of a Lie group…

Representation Theory · Mathematics 2019-07-17 Bas Janssens , Karl-Hermann Neeb

An l-group G is an abelian group equipped with a translation invariant lattice order. Baker and Beynon proved that G is finitely generated projective iff it is finitely presented. A unital l-group is an l-group G with a distinguished order…

Algebraic Topology · Mathematics 2009-07-20 Leonardo Cabrer , Daniele Mundici

Explicit embeddings of the group $\mathbb{Q}$ into a finitely presented group $\mathcal{Q}$ and into a $2$-generator finitely presented group $T_{\mathcal{Q}}$ are suggested. The constructed embeddings reflect questions mentioned by…

Group Theory · Mathematics 2023-10-18 V. H. Mikaelian

We construct every finite-dimensional irreducible representation of the simple Lie algebra of type $\mathsf{E}_{7}$ whose highest weight is a nonnegative integer multiple of the dominant minuscule weight associated with the type…

Representation Theory · Mathematics 2023-03-14 Robert G. Donnelly , Molly W. Dunkum , Austin White

In [2], an exhaustive construction is achieved for the class of all 4-dimensional unital division algebras over finite fields of odd order, whose left nucleus is not minimal and whose automorphism group contains Klein's four-group. We…

Rings and Algebras · Mathematics 2019-08-20 Ernst Dieterich

In [F. Caselli, Involutory reflection groups and their models, J. Algebra 24 (2010), 370--393] it is constructed a uniform Gelfand model for all non-exceptional irreducible complex reflection groups which are involutory. This model can be…

Combinatorics · Mathematics 2010-07-19 Fabrizio Caselli , Roberta Fulci

Inspired by Ol'shanskii's work, we provide an axiomatic framework to describe certain irreducible unitary representations of non-discrete unimodular totally disconnected locally compact groups. We then look at the applications to certain…

Group Theory · Mathematics 2022-03-10 Lancelot Semal

We propose an algorithm which for any recursive group $G$, given by its effectively enumerable generators and recursively enumerable relations, outputs an explicit embedding of $G$ into a finitely presented group directly written by its…

Group Theory · Mathematics 2026-01-22 V. H. Mikaelian

Craigen introduced and studied {\it signed group Hadamard matrices} extensively in \cite{Craigenthesis, Craigen}. Livinskyi \cite{Ivan}, following Craigen's lead, studied and provided a better estimate for the asymptotic existence of signed…

Combinatorics · Mathematics 2015-02-27 Ebrahim Ghaderpour

We introduce a construction that associates, to each finite dimensional k-vector space V, a family of projective k-varieties that comes equipped with the structure of a operad in the category of k-schemes. When dim V = 1, this operad…

Algebraic Geometry · Mathematics 2012-11-20 Tyler Foster

A unitary 2-design can be viewed as a quantum analogue of a 2-universal hash function: it is indistinguishable from a truly random unitary by any procedure that queries it twice. We show that exact unitary 2-designs on n qubits can be…

Quantum Physics · Physics 2017-01-03 Richard Cleve , Debbie Leung , Li Liu , Chunhao Wang

Let $G$ be an $\ell$-group (which is short for ``lattice-ordered abelian group''). Baker and Beynon proved that $G$ is finitely presented iff it is finitely generated and projective. In the category $\mathcal U$ of {\it unital}…

Group Theory · Mathematics 2010-06-23 Leonardo Cabrer , Daniele Mundici

The form factor of the unitary group U(N) endowed with the Haar measure characterizes the correlations within the spectrum of a typical unitary matrix. It can be decomposed into a sum over pairs of ``periodic orbits'', where by periodic…

Chaotic Dynamics · Physics 2007-05-23 G. Berkolaiko