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In the work we discuss two invariants of conjugacy classes of braids. The first invariant is the conformal module which occurred in connection with the interest in the 13th Hilbert Problem. The second is a popular dynamical invariant, the…

Geometric Topology · Mathematics 2023-12-20 Burglind Jöricke

Given a finite-dimensional inner product space $V$ and a group $G$ of isometries, we consider the problem of embedding the orbit space $V/G$ into a Hilbert space in a way that preserves the quotient metric as well as possible. This inquiry…

Metric Geometry · Mathematics 2025-06-06 Ben Blum-Smith , Harm Derksen , Dustin G. Mixon , Yousef Qaddura , Brantley Vose

For a closed manifold equipped with a Riemannian metric, a triangulation, a representation of its fundamental group on an Hilbert module of finite type (over of finite von Neumann algebra), and a Hermitian structure on the flat bundle…

dg-ga · Mathematics 2007-05-23 D. Burghelea , L. Friedlander , T. Kappeler

We introduce the notion of a directed stratification for a finite-dimensional algebra. For algebras that admit such a stratification we characterise the projective resolutions of finitely generated modules and obtain a result for the…

Representation Theory · Mathematics 2011-02-15 Karsten Dietrich

For an arbitrary self-adjoint operator $B$ in a Hilbert space $H$, we present direct and inverse theorems establishing the relationship between the degree of smoothness of a vector $x \in H$ with respect to the operator $B$, the rate of…

Functional Analysis · Mathematics 2007-09-27 S. M. Torba , M. L. Gorbachuk , Ya. I. Grushka

The category of quasi frames (or qframes) is introduced and studied. In the context of qframes we can jointly study problems related to the L-Surjunctivity and Stable Finiteness Conjectures. As a consequences of our main results, we can…

Rings and Algebras · Mathematics 2018-01-17 Simone Virili

There is a family of constructions to produce orthomodular structures from modular lattices, lattices that are M and M*-symmetric, relation algebras, the idempotents of a ring, the direct product decompositions of a set or group or…

Quantum Algebra · Mathematics 2013-11-13 John Harding , Taewon Yang

The conformal module of conjugacy classes of braids implicitly appeared in a paper of Lin and Gorin in connection with their interest in the 13. Hilbert Problem. This invariant is the supremum of conformal modules (in the sense of Ahlfors)…

Algebraic Geometry · Mathematics 2012-11-26 Burglind Jöricke

Let $R$ be a commutative Noetherian ring, $\fa$ an ideal of $R$ and $M$ a finitely generated $R$--module. Let $t$ be a non-negative integer such that $\H^i_\fa(M)$ is $\fa$--cofinite for all $i<t$. It is well--known that…

Commutative Algebra · Mathematics 2007-05-23 Mohammad T. Dibaei , Siamak Yassemi

We give a number of constructions where inverse limits seriously degrade properties of regular rings, such as unit-regularity, diagonalisation of matrices, and finite stable rank. This raises the possibility of using inverse limits to…

Rings and Algebras · Mathematics 2024-11-21 Pere Ara , Ken Goodearl , Kevin C. O'Meara , Enrique Pardo , Francesc Perera

We construct geometric generators of the effective $S^1$-equivariant Spin- (and oriented) bordism groups with two inverted. We apply this construction to the question of which $S^1$-manifolds admit invariant metrics of positive scalar…

Geometric Topology · Mathematics 2021-07-26 Michael Wiemeler

Let $H$ be a complex Hilbert space and let ${\mathcal P}(H)$ be the associated projective space (the set of rank-one projections). Suppose that $\dim H\ge 3$. We prove the following Wigner-type theorem: if $H$ is finite-dimensional, then…

Mathematical Physics · Physics 2020-12-04 Mark Pankov , Thomas Vetterlein

A refined notion of curvature for a linear system of Hermitian vector spaces, in the sense of Grothendieck, leads to the unitary classification of a large class of analytic Hilbert modules. Specifically, we study Hilbert sub-modules, for…

Spectral Theory · Mathematics 2009-09-11 Shibananda Biswas , Gadadhar Misra , Mihai Putinar

We consider a sequence H_N of Hilbert spaces of dimensions d_N tending to infinity. The motivating examples are eigenspaces or quasi-mode spaces of a Laplace or Schrodinger operator. We define a random ONB of H_N by fixing one ONB and…

Spectral Theory · Mathematics 2014-03-05 Steve Zelditch

We exhibit a finitely generated group $G$ and a sequence of finite index normal subgroups $N_n\trianglelefteq G$ such that for every finite generating subset $S\subseteq G$, the sequence of finite Cayley graphs $(G/N_n, S)$ does not…

Group Theory · Mathematics 2016-05-04 Goulnara Arzhantseva , Romain Tessera

For every H-space $X$ the set of homotopy classes $[X,X]$ possesses a natural algebraic structure of a loop near-ring. Albeit one cannot say much about general loop near-rings, it turns out that those that arise from H-spaces are…

Algebraic Topology · Mathematics 2016-12-21 Damir Franetič , Petar Pavešić

For a compact spinc manifold $X$ with boundary $b_1(\partial X)=0$, we consider moduli spaces of solutions to the Seiberg-Witten equations in a generalized double Coulomb slice in $L^2_1$ (i.e., $W^{1,2}$) Sobolev regularity. We prove they…

Differential Geometry · Mathematics 2021-12-07 Piotr Suwara

Based upon properties of ordinal length, we introduce a new class of modules, the binary modules, and study their endomorphism ring. The nilpotent endomorphisms form a two-sided ideal, and after factoring this out, we get a commutative…

Commutative Algebra · Mathematics 2012-12-11 Hans Schoutens

In the presence of a nontrivial dual Selmer group, certain global even deformation rings are shown to be finite and flat over $\mathbb{Z}_p$. Previously, flatness was only known in established cases of Langlands reciprocity in the odd…

Number Theory · Mathematics 2026-04-01 Peter Vang Uttenthal

We will use commutators to provide decompositions of $3\times 3$ matrices as sums whose terms satisfy some polynomial identities, and we apply them to bounded linear operators and endomorphisms of free modules of infinite rank. In…

Rings and Algebras · Mathematics 2022-09-08 Simion Breaz , Cristian Rafiliu