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Related papers: A Schur-Horn type theorem for II$_1$ factors

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A few years ago, Richard Kadison thoroughly analysed the diagonals of projection operators on Hilbert spaces and asked the following question: Let $\mathcal{A}$ be a masa in a type $II_1$ factor $\mathcal{M}$ and let $A \in \mathcal{A}$ be…

Operator Algebras · Mathematics 2014-11-19 Mohan Ravichandran

The carpenter problem in the context of $II_1$ factors, formulated by Kadison asks: Let $\mathcal{A} \subset \mathcal{M}$ be a masa in a type $II_1$ factor and let $E$ be the normal conditional expectation from $\mathcal{M}$ onto…

Operator Algebras · Mathematics 2011-11-17 B. V. Rajarama Bhat , Mohan Ravichandran

A theorem of Thompson provides a non-self-adjoint variant of the classical Schur-Horn theorem by characterizing the possible diagonal values of a matrix with given singular values. We prove an analogue of Thompson's theorem for II_1…

Operator Algebras · Mathematics 2017-05-09 Matthew Kennedy , Paul Skoufranis

We describe majorization between selfadjoint operators in a $\sigma$-finite II$_\infty$ factor $(\mathcal{M},\tau)$ in terms of simple spectral relations. For a diffuse abelian von Neumann subalgebra $\mathcal{A}\subset \mathcal{M}$ with…

Operator Algebras · Mathematics 2013-04-05 Martin Argerami , Pedro Massey

Let M be a II_1 factor, A a masa in M and E the unique conditional expectation on A. Under some technical assumptions on the inclusion of A in M, which hold true for any semiregular masa of a separable factor, we show that for every…

Operator Algebras · Mathematics 2011-06-01 Martin Argerami , Pedro Massey

Two classical theorems in matrix theory, due to Schur and Horn, relate the eigenvalues of a self-adjoint matrix to the diagonal entries. These have recently been given a formulation in the setting of operator algebras as the Schur-Horn…

Operator Algebras · Mathematics 2011-11-01 Ken Dykema , Junsheng Fang , Don Hadwin , Roger Smith

We obtain the analogue of Schur-Weyl duality for the unitary group of an arbitrary ${\rm II}_1$-factor

Representation Theory · Mathematics 2013-12-04 N. I. Nessonov

We prove a variety of results describing the possible diagonals of tuples of commuting hermitian operators in type $II_1$ factors. These results are generalisations of the classical Schur-Horn theorem to the infinite dimensional,…

Operator Algebras · Mathematics 2017-05-17 Pedro Massey , Mohan Ravichandran

We show that the unitary group of any SOT-separable $\mathrm{II}_1$ factor $M$, with the strong operator topology, is contractible. Combined with several old results, this implies that the same is true for any SOT-separable von Neumann…

Operator Algebras · Mathematics 2025-09-04 David Jekel

This paper addresses a conjecture of Kadison and Kastler that a von Neumann algebra M on a Hilbert space H should be unitarily equivalent to each sufficiently close von Neumann algebra N and, moreover, the implementing unitary can be chosen…

Operator Algebras · Mathematics 2013-07-30 Jan Cameron , Erik Christensen , Allan M. Sinclair , Roger R. Smith , Stuart White , Alan D. Wiggins

We characterize the set of diagonals of the unitary orbit of a self-adjoint operator with three points in the spectrum. Our result gives a Schur-Horn theorem for operators with three point spectrum analogous to Kadison's result for…

Functional Analysis · Mathematics 2013-09-16 John Jasper

We prove a Kurosh type theorem for free-product type II_1 factors. In particular, if M = LF_2 \otimes R, then the free-product type II_1 factors M*...*M are all prime and pairwise non-isomorphic. This paper is a continuation of [N. Ozawa,…

Operator Algebras · Mathematics 2011-11-10 Narutaka Ozawa

In this paper we prove the Cheeger-M\"{u}ller theorem for $L^2$-analytic torsion form under the assumption that there exists a fiberwise Morse function and the Novikov-Shubin invariant is positive.

Differential Geometry · Mathematics 2018-05-29 Guangxiang Su

This is a continuation of our previous paper studying the structure of Cartan subalgebras of von Neumann factors of type II_1. We provide more examples of II_1 factors having either zero, one or several Cartan subalgebras. We also prove a…

Operator Algebras · Mathematics 2008-07-29 Narutaka Ozawa , Sorin Popa

We prove that a Schur function of rectangular shape $(M^n)$ whose variables are specialized to $x_1,x_1^{-1},...,x_n,x_n^{-1}$ factorizes into a product of two odd orthogonal characters of rectangular shape, one of which is evaluated at…

Combinatorics · Mathematics 2010-01-18 Mihai Ciucu , Christian Krattenthaler

We consider the Schur-Horn problem for normal operators in von Neumann algebras, which is the problem of characterizing the possible diagonal values of a given normal operator based on its spectral data. For normal matrices, this problem is…

Operator Algebras · Mathematics 2015-10-28 Matthew Kennedy , Paul Skoufranis

We prove the Strengthened Hanna Neumann Conjecture, in its common graph theoretic formulation. Our original approach to this conjecture used cohomology of sheaves on graphs, although here we give a short combinatorial proof that we found in…

Combinatorics · Mathematics 2011-04-15 Joel Friedman

We characterize the set of diagonals of the unitary orbit of a self-adjoint operator with a finite spectrum. Our result extends the Schur-Horn theorem from a finite dimensional setting to an infinite dimensional Hilbert space analogous to…

Functional Analysis · Mathematics 2013-02-21 Marcin Bownik , John Jasper

We show that a number of key structural properties transfer between sufficiently close II$_1$ factors, including solidity, strong solidity, uniqueness of Cartan masas and property $\Gamma$. We also examine II$_1$ factors close to tensor…

Operator Algebras · Mathematics 2016-06-01 Jan Cameron , Erik Christensen , Allan M. Sinclair , Roger R. Smith , Stuart White , Alan D. Wiggins

We start with a bijective proof of Schur's theorem due to Alladi and Gordon and describe how a particular iteration of it leads to some very general theorems on colored partitions. These theorems imply a number of important results,…

Combinatorics · Mathematics 2007-09-11 Sylvie Corteel , Jeremy Lovejoy
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