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We introduce and analyse ensembles of 2-regular random graphs with a tuneable distribution of short cycles. The phenomenology of these graphs depends critically on the scaling of the ensembles' control parameters relative to the number of…

Disordered Systems and Neural Networks · Physics 2018-02-14 Fabian Aguirre Lopez , Paolo Barucca , Mathilde Fekom , Anthony CC Coolen

A discrete analog of a skew selfadjoint canonical (Zakharov-Shabat or AKNS) system with a pseudo-exponential potential is introduced. For the corresponding Weyl function the direct and inverse problem are solved explicitly in terms of three…

Spectral Theory · Mathematics 2007-05-23 M. A. Kaashoek , A. L. Sakhnovich

We present quadrature schemes to calculate matrices, where the so-called modified Hilbert transformation is involved. These matrices occur as temporal parts of Galerkin finite element discretizations of parabolic or hyperbolic problems when…

Numerical Analysis · Mathematics 2022-07-26 Marco Zank

We apply the approach developed in our previous papers to obtain examples of solutions to the inverse spectral problem (ISP) for the canonical Hamiltonian system. One of our goals is to illustrate connections of ISP with classical tools of…

Complex Variables · Mathematics 2025-09-16 Nikolai Makarov , Alexei Poltoratski

We study the density of the supremum of a strictly stable L\'evy process. As was proved recently in F. Hubalek and A. Kuznetsov "A convergent series representation for the density of the supremum of a stable process" (Elect. Comm. in…

Probability · Mathematics 2011-12-20 Alexey Kuznetsov

A regular sampling theory in a multiply generated unitary invariant subspace of a separable Hilbert space $\mathcal{H}$ is proposed. This subspace is associated to a unitary representation of a countable discrete abelian group $G$ on…

Functional Analysis · Mathematics 2020-01-16 Antonio G. García , Miguel A. Hernández-Medina , Gerardo Pérez-Villalón

Associative conformal algebras of conformal endomorphisms are of essential importance for the study of finite representations of conformal Lie algebras (Lie vertex algebras). We describe all semisimple algebras of conformal endomorphisms…

Quantum Algebra · Mathematics 2019-12-10 P. S. Kolesnikov , R. A. Kozlov

We study equivariant affine embeddings of homogeneous spaces and their equivariant automorphisms. An example of a quasiaffine, but not affine, homogeneous space with finitely many equivariant automorphisms is presented. We prove the…

Algebraic Geometry · Mathematics 2009-10-03 Ivan V. Arzhantsev , Dmitri A. Timashev

The spectrum $\omega(G)$ is the set of orders of elements of $G$. We consider the problem of generating the spectrum of a finite nonabelian simple group $G$ given by the degree of $G$ if $G$ is an alternating group, or the Lie type, Lie…

Group Theory · Mathematics 2021-09-28 Alexander Buturlakin

We study the estimation, in Lp-norm, of density functions defined on [0,1]^d. We construct a new family of kernel density estimators that do not suffer from the so-called boundary bias problem and we propose a data-driven procedure based on…

Statistics Theory · Mathematics 2018-10-29 Karine Bertin , Salima El Kolei , Nicolas Klutchnikoff

A version of the iterated B\"acklund-Darboux transformation, where Darboux matrix takes a form of the transfer matrix function from the system theory, is constructed for the discrete canonical system and Non-Abelian Toda lattice. Results on…

Exactly Solvable and Integrable Systems · Physics 2007-05-23 Alexander Sakhnovich

A recently proposed discrete version of the Schrodinger spectral problem is considered. The whole hierarchy of differential-difference nonlinear evolution equations associated to this spectral problem is derived. It is shown that a discrete…

Exactly Solvable and Integrable Systems · Physics 2009-11-07 M. Boiti , M. Bruschi , F. Pempinelli , B. Prinari

Discrete analogs of the Lebedev-Skalskaya transforms are introduced and investigated. It involves series and integrals with respect to the kernels ${\rm Re} K_{\alpha+in}(x), {\rm Im} K_{\alpha+in}(x), x >0, n \in \mathbb{N}, |\alpha | <…

Classical Analysis and ODEs · Mathematics 2020-09-01 Semyon Yakubovich

Using the results of J. Arthur on the representation theory of classical groups with additional work by Colette Moeglin and its relation with representations of affine Hecke algebras established by the author, we show that the category of…

Representation Theory · Mathematics 2016-03-07 Volker Heiermann

Commuting transfer matrices for linear chains of interacting non-Abelian anyons from the two-dimensional irreducible representation of the dihedral group $D_3$ (or, equivalently, the integer sector of the $su(2)_4$ spin-$1$ chain) are…

Strongly Correlated Electrons · Physics 2016-08-31 Natalia Braylovskaya , Peter E. Finch , Holger Frahm

We study spectral properties of two-dimensional canonical systems $y'(t)=zJH(t)y(t)$, $t\in[a,b)$, where the Hamiltonian $H$ is locally integrable on $[a,b)$, positive semidefinite, and Weyl's limit point case takes place at $b$. We answer…

Spectral Theory · Mathematics 2019-04-09 Roman Romanov , Harald Woracek

We obtain spectral asymptotics for the quantized derivatives of elements from the first-order homogeneous Sobolev space on the quantum Euclidean space, extending an earlier result of McDonald, Sukochev and Xiong (Commun. Math. Phys. 2020).…

Functional Analysis · Mathematics 2025-05-20 Yongqiang Tian

A finite sampling theory associated with a unitary representation of a finite non Abelian group $\mathbf{G}$ on a Hilbert space is stablished. The non Abelian group $\mathbf{G}$ is a knit product $\mathbf{N}\bowtie \mathbf{H}$ of two finite…

Functional Analysis · Mathematics 2018-07-02 Antonio G. García , Miguel A. Hernández-Medina , Albert Ibort

A certain representation for the Heisenberg algebra in finite-difference operators is established. The Lie-algebraic procedure of discretization of differential equations with isospectral property is proposed. Using $sl_2$-algebra based…

funct-an · Mathematics 2009-10-28 Yuri Smirnov , Alexander Turbiner

It is well-known that characters classify linear representations of finite groups, that is if characters of two representations of a finite group are the same, these representations are equivalent. It is also well-known that, in general,…

Group Theory · Mathematics 2024-03-14 Michael Stessin