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Making use of its smooth structure only, out of a connected oriented smooth $4$-manifold a von Neumann algebra is constructed. It is geometric in the sense that is generated by local operators and as a special four dimensional phenomenon it…

Mathematical Physics · Physics 2024-04-09 Gabor Etesi

Let $Y$ be a compact Gorenstein analytic space with only isolated singularities and trivial dualizing sheaf. A recent paper of Imagi studies the deformation theory of $Y$ in case the singularities of $Y$ are weighted homogeneous and…

Algebraic Geometry · Mathematics 2026-02-16 Robert Friedman

Let $\mathcal{V} \subset M$ denote any of the varieties of singular $m \times m$ complex matrices which may be general, symmetric, or skew-symmetric ($m$ even), or $m \times p$ matrices, in the corresponding space $M$ of such matrices. A…

Algebraic Geometry · Mathematics 2019-11-07 James Damon

Given an irreducible local conformal net A of von Neumann algebras on the circle and a finite-index conformal subnet B of A, we show that A is completely rational iff B is completely rational. In particular this extends a result of F. Xu…

Operator Algebras · Mathematics 2011-04-06 Roberto Longo

The Newlander-Nirenberg theorem says that a necessary and sufficient condition for the complex coordinates associated with a given almost complex structure tensor $I_M{}^N$ to exist is the vanishing of the Nijenhuis tensor ${\cal…

Mathematical Physics · Physics 2020-03-05 Andrei Smilga

In this note we include two remarks about bounded ($\underline{not}$ necessarily contractive) linear projections on a von Neumann-algebra. We show that if $M$ is a von Neumann-subalgebra of $B(H)$ which is complemented in B(H) and…

Operator Algebras · Mathematics 2009-09-25 Gilles Pisier

A singular (or Hermann) foliation on a smooth manifold $M$ can be seen as a subsheaf of the sheaf $\mathfrak{X}$ of vector fields on $M$. We show that if this singular foliation admits a resolution (in the sense of sheaves) consisting of…

Differential Geometry · Mathematics 2018-07-20 Sylvain Lavau

This paper investigates the structure of Verma modules over the N=1 BMS superalgebra. We provide a detailed classification of singular vectors, establish necessary and sufficient conditions for the existence of subsingular vectors, uncover…

Representation Theory · Mathematics 2024-12-24 Wei Jiang , Dong Liu , Yufeng Pei , Kaiming Zhao

Every unital nonselfadjoint operator algebra possesses canonical and functorial classes of faithful (even completely isometric) Hilbert space representations satisfying a double commutant theorem generalizing von Neumann's classical result.…

Operator Algebras · Mathematics 2007-05-23 David P. Blecher , Baruch Solel

A notion of partial ideal for an operator algebra is a weakening the notion of ideal where the defining algebraic conditions are enforced only in the commutative subalgebras. We show that, in a von Neumann algebra, the ultraweakly closed…

Operator Algebras · Mathematics 2014-08-07 Nadish de Silva , Rui Soares Barbosa

For each sequence $\{c_n\}_n$ in $l_{1}(\N)$ we define an operator $A$ in the hyperfinite $\mathrm{II}_1$-factor $\mathcal{R}$. We prove that these operators are quasinilpotent and they generate the whole hyperfinite $\mathrm{II}_1$-factor.…

Operator Algebras · Mathematics 2007-08-16 Gabriel H. Tucci

We initiate a study of maximal subgroups and maximal von Neumann subalgebras which have the Haagerup property. We determine maximal Haagerup subgroups inside $\mathbb{Z}^2 \rtimes SL_2(\mathbb{Z})$ and obtain several explicit instances…

Operator Algebras · Mathematics 2021-08-11 Yongle Jiang , Adam Skalski

This is a survey article of geometric properties of noncommutative symmetric spaces of measurable operators $E(\mathcal{M},\tau)$, where $\mathcal{M}$ is a semifinite von Neumann algebra with a faithful, normal, semifinite trace $\tau$, and…

Operator Algebras · Mathematics 2017-04-10 Malgorzata Marta Czerwinska , Anna Kaminska

We study the partial resolutions of singularities related to Hilbert schemes of points on an affine space. Consider a quotient of a vector space $V$ by an action of a finite group $G$ of linear transforms. Under some additional assumptions,…

Algebraic Geometry · Mathematics 2007-05-23 D. Kaledin , M. Verbitsky

Let $H$ be an infinite-dimensional Hilbert space. We prove that every unconditional Schauder frame for $H$ contains a subsequence that can be normalized to form a frame for $H$. As a consequence, every semi-normalized unconditional Schauder…

Classical Analysis and ODEs · Mathematics 2026-03-16 Pu-Ting Yu

We establish a closed formula for a singular vector of weight $\lambda-\beta$ in the Verma module of highest weight $\lambda$ for Lie superalgebra $\mathfrak{gl}(m|n)$ when $\lambda$ is atypical with respect to an odd positive root $\beta$.…

Representation Theory · Mathematics 2020-07-07 Jie Liu , Li Luo , Weiqiang Wang

In this paper we prove that whenever $G$ is hyperbolic relative to a family of exact, ressidually finite subgroups $\{H_1, \ldots, H_n\}$, the corresponding von Neumann algebra $\mathcal L(G)$ is solid relative to the family of subalgebras…

Operator Algebras · Mathematics 2025-09-25 Juan Felipe Ariza Mejia , Dulanji Nikethani Amaraweera , Ionut Chifan , Krishnendu Khan

Let $\M$ be a von Neumann algebra with a faithful normal trace $\T$, and let $H^\infty$ be a finite, maximal, subdiagonal algebra of $\M$. Fundamental theorems on conjugate functions for weak$^*$\!-Dirichlet algebras are shown to be valid…

Operator Algebras · Mathematics 2016-09-06 Narcisse Randrianantoanina

We study modular theory in hyperfinite von Neumann algebras, i.e. in those of type II or type III, from the viewpoint of a subregion charge sector decomposition. We address this symmetry resolution by considering infinite tensor products of…

High Energy Physics - Theory · Physics 2025-10-06 Giuseppe Di Giulio , Moritz Dorband , Johanna Erdmenger , Henri Scheppach

Given a von Neumann algebra $M$ we introduce so called central extension $mix(M)$ of $M$. We show that $mix(M)$ is a *-subalgebra in the algebra $LS(M)$ of all locally measurable operators with respect to $M,$ and this algebra coincides…

Operator Algebras · Mathematics 2009-08-11 Shavkat A. Ayupov , Karimbergen K. Kudaybergenov