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We call a von Neumann algebra with finite dimensional center a multifactor. We introduce an invariant of bimodules over $\rm II_1$ multifactors that we call modular distortion, and use it to formulate two classification results. We first…

Operator Algebras · Mathematics 2025-06-06 Marcel Bischoff , Ian Charlesworth , Samuel Evington , Luca Giorgetti , David Penneys

This work connects two mathematical fields - computational complexity and interval linear algebra. It introduces the basic topics of interval linear algebra - regularity and singularity, full column rank, solving a linear system, deciding…

Computational Complexity · Computer Science 2016-02-02 Jaroslav Horáček , Milan Hladík , Michal Černý

Compositionality is a key property for dealing with complexity, which has been studied from many points of view in diverse fields. Particularly, the composition of individual computations (or programs) has been widely studied almost since…

Logic in Computer Science · Computer Science 2022-06-06 Damian Arellanes

In this article we give a short and informal overview of some aspects of the theory of C*- and von Neumann algebras. We also mention some classical results and applications of these families of operator algebras.

Operator Algebras · Mathematics 2013-04-12 Fernando Lledó

Could elementary complex analysis, which covers the topics such as algebra of complex numbers, elementary complex functions, complex differentiation and integration, series expansions of complex functions, residues and singularities, and…

Complex Variables · Mathematics 2016-10-27 Agamirza E. Bashirov , Sajedeh Norozpour

We consider the problem of computing the Euler characteristic of an abstract simplicial complex given by its vertices and facets. We show that this problem is #P-complete and present two new practical algorithms for computing Euler…

Computational Geometry · Computer Science 2011-12-21 Bjarke Hammersholt Roune , Eduardo Sáenz de Cabezón

In this paper we develop the theory of strongly singular subalgebras of von Neumann algebras, begun in earlier work. We mainly examine the situation of type $\tto$ factors arising from countable discrete groups. We give simple criteria for…

Operator Algebras · Mathematics 2013-02-26 Guyan Robertson , Allan M. Sinclair , Roger R. Smith

The notion of index for arbitrary real factors is introduced and investigated. The main tool in our approach is the reduction of real factors to involutive *-anti-automorphisms of their complex enveloping von Neumann algebras. Similar to…

Operator Algebras · Mathematics 2011-06-15 S. Albeverio , Sh. A. Ayupov , A. A. Rakhimov , R. A. Dadakhodjaev

The notion of index for inclusions of von Neumann algebras goes back to a seminal work of Jones on subfactors of type ${I\!I}_1$. In the absence of a trace, one can still define the index of a conditional expectation associated to a…

Operator Algebras · Mathematics 2022-05-04 Luca Giorgetti

The theory of computational complexity is used to underpin a recent model of neocortical sensory processing. We argue that encoding into reconstruction networks is appealing for communicating agents using Hebbian learning and working on…

Neurons and Cognition · Quantitative Biology 2007-05-23 Andras Lorincz

We study regular inclusions of finite-dimensional von Neumann algebras from a matrix-theoretic perspective. To this end, we introduce a new combinatorial invariant of an inclusion, called the normalizer matrix, which encodes the structure…

Operator Algebras · Mathematics 2026-02-18 Keshab Chandra Bakshi , Silambarasan C

A family of partial functions of a class of algebras $\mathsf{K}$ is said to be an implicit operation of $\mathsf{K}$ when it is defined by a first order formula and it is preserved by homomorphisms. In this work, we develop the theory of…

Rings and Algebras · Mathematics 2026-04-24 Luca Carai , Miriam Kurtzhals , Tommaso Moraschini

A certain class of matrix-valued Borel matrix functions is introduced and it is shown that all functions of that class naturally operate on any operator T in a finite type I von Neumann algebra M in a way such that uniformly bounded…

Operator Algebras · Mathematics 2017-05-26 Piotr Niemiec

Weihrauch complexity is now an established and active part of mathematical logic. It can be seen as a computability-theoretic approach to classifying the uniform computational content of mathematical problems. This theory has become an…

Logic · Mathematics 2023-02-09 Vasco Brattka

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

Computational complexity is a new quantum information concept that may play an important role in holography and in understanding the physics of the black hole interior. We consider quantum computational complexity for $n$ qubits using…

High Energy Physics - Theory · Physics 2021-05-21 Roberto Auzzi , Stefano Baiguera , G. Bruno De Luca , Andrea Legramandi , Giuseppe Nardelli , Nicolò Zenoni

For certain problems involving vector fields, it is possible to find an associated imaginary field that, in conjunction with the first, forms a complex field for which the equation can be solved. This result is generalized to arbitrary…

Differential Geometry · Mathematics 2007-05-23 Dennis Hou

We introduce a new class of extensions of terms that consists in navigation strategies and insertion of contexts. We introduce an operation of combination on this class which is associative, admits a neutral element and so that each…

Logic in Computer Science · Computer Science 2019-04-25 Walid Belkhir , Nicolas Ratier , Duy Duc Nguyen Michel Lenczner

We initiate and study the theory of ``real decomposable maps" between real operator systems. Formally, this is new even in the complex case, which hitherto has restricted itself to the case where the systems are complex C*-algebras. We…

Operator Algebras · Mathematics 2026-05-11 David P. Blecher , Christiaan H. Pretorius

We are able to explicitly compute the bimodule structure of von Neumann algebra inclusions in handle constructions, which arise as inductive limits of iterated amalgamated free products not elementarily equivalent to $L(\mathbb{F}_2)$. Our…

Operator Algebras · Mathematics 2026-02-03 David Gao , David Jekel , Srivatsav Kunnawalkam Elayavalli , Gregory Patchell