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We answer the following question posed by Lechuga: Given a simply-connected space $X$ with both $H_*(X,\qq)$ and $\pi_*(X)\otimes \qq$ being finite-dimensional, what is the computational complexity of an algorithm computing the cup-length…

Algebraic Topology · Mathematics 2011-12-06 Manuel Amann

The purpose of this note is to show that the construction of the C*-algebra for the space-time uncertainty relations which was introduced by Doplicher, Fredenhagen and Roberts fits comfortably into the strict deformation quantization…

funct-an · Mathematics 2008-02-03 Marc A. Rieffel

We introduce and study a parametrized analogue of the directed topological complexity, originally developed by Goubault, Farber, and Sagnier. We establish the fibrewise basic dihomotopy invariance of directed parametrized topological…

Algebraic Topology · Mathematics 2025-12-04 Sutirtha Datta , Navnath Daundkar , Abhishek Sarkar

While there is only one natural dimension concept for separable, metric spaces, the theory of dimension in noncommutative topology ramifies into different important concepts. To accommodate this, we introduce the abstract notion of a…

Operator Algebras · Mathematics 2015-01-06 Hannes Thiel

We find conditions which ensure that the topological complexity of a closed manifold $M$ with abelian fundamental group is nonmaximal, and see through examples that our conditions are sharp. This generalizes results of Costa and Farber on…

Algebraic Topology · Mathematics 2021-09-10 Daniel C. Cohen , Lucile Vandembroucq

By analogy with the invariant Q-category defined by Scheerer, Stanley and Tanr\'e, we introduce the notions of Q-sectional category and Q-topological complexity. We establish several properties of these invariants. We also obtain a formula…

Algebraic Topology · Mathematics 2017-01-23 Lucía Fernández Suárez , Lucile Vandembroucq

We introduce a notion of a uniform structure on the set of all representations of a given separable, not necessarilly commutative $C^*$-algebra $\mathfrak{A}$ by introducing a suitable family of metrics on the set of representations of…

Operator Algebras · Mathematics 2018-05-17 Adam Wegert

In this paper we determine the topological complexity of configuration spaces of graphs which are not necessarily trees, which is a crucial assumption in previous results. We do this for two very different classes of graphs: fully…

Algebraic Topology · Mathematics 2019-04-12 Daniel Lütgehetmann , David Recio-Mitter

We make some brief remarks on the relation of the mixmaster universe model of chaotic cosmology to the geometry of modular curves and to noncommutative geometry. In particular we consider a class of solutions with bounded number of cycles…

Mathematical Physics · Physics 2007-05-23 Matilde Marcolli

We consider finite approximations of a topological space $M$ by noncommutative lattices of points. These lattices are structure spaces of noncommutative $C^*$-algebras which in turn approximate the algebra $\cc(M)$ of continuous functions…

High Energy Physics - Theory · Physics 2010-11-19 G. Bimonte , E. Ercolessi , G. Landi , F. Lizzi , G. Sparano , P. Teotonio-Sobrinho

To a given tiling a non commutative space and the corresponding C*-algebra are constructed. This includes the definition of a topology on the groupoid induced by translations of the tiling. The algebra is also the algebra of observables for…

Statistical Mechanics · Physics 2016-08-31 Johannes Kellendonk

Gelfand-Naimark duality (Commutative $C^*$-algebras $\equiv$ Locally compact Hausdorff spaces) is extended to $C^*$-algebras $\equiv$ Quotient maps on locally compact Hausdorff spaces. Using this duality, we give for an \emph{arbitrary}…

Functional Analysis · Mathematics 2007-05-23 Mukul S. Patel

In this paper, we introduce a Fourier-type formalism on non-commutative spaces. As a result, we obtain two versions of Hormander-Mikhlin Lp-multiplier theorem: on locally compact Kac groups and on semi-finite von Neumann algebras,…

Operator Algebras · Mathematics 2026-03-10 Rauan Akylzhanov , Michael Ruzhansky , Kanat Tulenov

We introduce two new formulations for the notion of "quantum metric on noncommutative space". For a compact noncommutative space associated to a unital C*-algebra, our quantum metrics are elements of the spatial tensor product of the…

Operator Algebras · Mathematics 2016-06-15 Maysam Maysami Sadr

The Gelfand - Na\u{i}mark theorem supplies the one to one correspondence between commutative $C^*$-algebras and locally compact Hausdorff spaces. So any noncommutative $C^*$-algebra can be regarded as a generalization of a topological…

Operator Algebras · Mathematics 2016-07-07 Petr Ivankov

Michael Farber introduced the Lusternik-Schnirelmann category cat$(M,\xi)$ for the pair of finite CW complex $M$ and first-order cohomology $\xi$. It is inspired by the Morse-Novikov theory, which is a closed 1-form version of the Morse…

Differential Geometry · Mathematics 2023-12-15 Fukushi Kenji

The notion and theory of the quantum space of all maps from a quantum space pioneered by So{\l}tan have been mainly focused on finite-dimensional C*-algebras which are matrix algebra bundles over a finite set $S$. We propose a modification…

Quantum Algebra · Mathematics 2018-10-23 Albert Jeu-Liang Sheu , Thomas Timmermann

We define a new version of Topological Complexity (TC) of a space, denoted as $\text{dTC}$, which, we think, fits better for motion planning for some autonomous systems. Like Topological complexity, \text{dTC} is also a homotopy invariant.…

Geometric Topology · Mathematics 2024-09-09 Alexander Dranishnikov , Ekansh Jauhari

Characterization of the *-subalgebras in the algebra of bounded operators acting on Hilbert space is presented. Sufficient conditions for the existence of a faithful representation in pre-Hilbert space of a *-algebra in terms of its…

Operator Algebras · Mathematics 2008-05-12 Stanislav Popovych

The Lusternik-Schnirelmann category cat and topological complexity TC are related homotopy invariants. The topological complexity TC has applications to the robot motion planning problem. We calculate the Lusternik-Schnirelmann category and…

Algebraic Topology · Mathematics 2019-11-12 Cesar A. Ipanaque Zapata