Results 51 to 60 of about 17,484 (160)

Toeplitz Extensions in Noncommutative Topology and Mathematical Physics

, 2020
AbstractWe review the theory of Toeplitz extensions and their role in operator K-theory, including Kasparov’s bivariant K-theory. We then discuss the recent applications of Toeplitz algebras in the study of solid-state systems, focusing in particular on the bulk-edge correspondence for topological insulators.
Arici, F., Mesland, B.
openaire   +3 more sources

A New Fixed‐Point Framework for Nonexpansive and Averaged Mappings in Normed GE‐Algebras

Journal of Mathematics, Volume 2026, Issue 1, 2026.
In this paper, we develop a systematic framework for studying fixed‐point theory in the setting of normed GE‐algebras. Building on the GE‐norm, we introduce and analyze nonexpansive mappings, α‐averaged mappings, and enriched contractions with respect to the quasimetric induced by the GE‐norm.
Prashant Patel, Ravikumar Bandaru, Amal S. Alali, Erhan Güler   +3 more
wiley   +1 more source

Quantum polydisk, quantum ball, and a q-analog of Poincar\'e's theorem

, 2013
The classical Poincar\'e theorem (1907) asserts that the polydisk $\mathbb D^n$ and the ball $\mathbb B^n$ in $\mathbb C^n$ are not biholomorphically equivalent for $n\ge 2$.
Pirkovskii, A. Yu.
core   +1 more source

Topological K‐theory of quasi‐BPS categories for Higgs bundles

Journal of Topology, Volume 18, Issue 4, December 2025.
Abstract In a previous paper, we introduced quasi‐BPS categories for moduli stacks of semistable Higgs bundles. Under a certain condition on the rank, Euler characteristic, and weight, the quasi‐BPS categories (called BPS in this case) are noncommutative analogues of Hitchin integrable systems.
Tudor Pădurariu, Yukinobu Toda
wiley   +1 more source

Duality in noncommutative topologically massive gauge field theory revisited [PDF]

The European Physical Journal C, 2004
14 pages, Latex. v2: comments and references added, minor changes. v3: analysis extended to the second order in the noncommutative parameter, references and discussions added.
Cantcheff, M. B., Minces, P.
openaire   +3 more sources

Twisted convolution and Moyal star product of generalized functions

, 2012
We consider nuclear function spaces on which the Weyl-Heisenberg group acts continuously and study the basic properties of the twisted convolution product of the functions with the dual space elements.
B. S. Mityagin, D. H. T. Franco, E. Brüning, F. A. Berezin, G. Köthe, H. H. Schaefer, I. M. Gel’fand, J. M. Gracia-Bondia, J. M. Maillard, J. Neumann von, L. Hormander, L. Álvarez-Gaumé, M. A. Antonets, M. A. Antonets, M. A. Antonets, M. A. Soloviev, M. A. Soloviev, M. A. Soloviev, M. A. Soloviev, M. A. Soloviev, M. A. Soloviev, M. A. Soloviev, M. A. Soloviev, M. A. Soloviev, M. A. Soloviev, M. Chaichian, M. Morimoto, M. Morimoto, N. Seiberg, O. W. Greenberg, R. Estrada, R. J. Szabo, S. Doplicher, S. Doplicher, V. E. Hubeny, V. Gayral, V. I. Arnold, V. P. Palamodov, V. V. Zharinov   +38 more
core   +1 more source

Average‐Case Matrix Discrepancy: Satisfiability Bounds

Random Structures &Algorithms, Volume 67, Issue 3, October 2025.
ABSTRACT Given a sequence of d×d$$ d\times d $$ symmetric matrices {Wi}i=1n$$ {\left\{{\mathbf{W}}_i\right\}}_{i=1}^n $$, and a margin Δ>0$$ \Delta >0 $$, we investigate whether it is possible to find signs (ε1,…,εn)∈{±1}n$$ \left({\varepsilon}_1,\dots, {\varepsilon}_n\right)\in {\left\{\pm 1\right\}}^n $$ such that the operator norm of the signed sum ...
Antoine Maillard
wiley   +1 more source

Compact group actions on topological and noncommutative joins

Proceedings of the American Mathematical Society, 2018
We consider the Type 1 and Type 2 noncommutative Borsuk-Ulam conjectures of Baum, D$ $browski, and Hajac: there are no equivariant morphisms $A \to A \circledast_ H$ or $H \to A \circledast_ H$, respectively, when $H$ is a nontrivial compact quantum group acting freely on a unital $C^*$-algebra $A$.
Chirvasitu, Alexandru, Passer, Benjamin
openaire   +3 more sources

Connes distance by examples: Homothetic spectral metric spaces

, 2012
We study metric properties stemming from the Connes spectral distance on three types of non compact noncommutative spaces which have received attention recently from various viewpoints in the physics literature.
Cagnache E., Cagnache E., Connes A., Connes A., d'Andrea F., de Goursac A., Grosse H., JEAN-CHRISTOPHE WALLET, Landi G., Langmann E., Latrémolière F., Renardy M., Rieffel M. A., Rieffel M. A., Rieffel M. A., Rieffel M. A., Wallet J.-C.   +16 more
core   +1 more source

Heisenberg‐smooth operators from the phase‐space perspective

Mathematische Nachrichten, Volume 298, Issue 8, Page 2845-2866, August 2025.
Abstract Cordes' characterization of Heisenberg‐smooth operators bridges a gap between the theory of pseudo‐differential operators and quantum harmonic analysis (QHA). We give a new proof of the result by using the phase‐space formalism of QHA. Our argument is flexible enough to generalize Cordes' result in several directions: (1) we can admit general ...
Robert Fulsche, Lauritz van Luijk
wiley   +1 more source