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It is shown that van Suijlekom's technique of imposing a set of conditions on operator system spectral triples ensures Gromov-Hausdorff convergence of sequences of sets of unital completely positive maps (equipped with the BW-topology which…

Operator Algebras · Mathematics 2025-02-27 Tirthankar Bhattacharyya , Ritul Duhan , Chandan Pradhan

Two examples of spectral triples with non-integer dimension spectrum are considered. These triples involve commutative C*-algebras. The first example has complex dimension spectrum and trivial differential algebra. The other is a parameter…

Mathematical Physics · Physics 2008-09-29 R. Trinchero

A proper etale Lie groupoid is modelled as a (noncommutative) spectral geometric space. The spectral triple is built on the algebra of smooth functions on the groupoid base which are invariant under the groupoid action. Stiefel-Whitney…

Mathematical Physics · Physics 2014-12-16 Antti J. Harju

We extend the notion of a spectral triple to that of a higher-order relative spectral triple, which accommodates several types of hypoelliptic differential operators on manifolds with boundary. The bounded transform of a higher-order…

K-Theory and Homology · Mathematics 2024-06-05 Magnus Fries

We study countable sums of two dimensional modules for the continuous complex functions on a compact metric space and show that it is possible to construct a spectral triple which gives the original metric back. This spectral triple will be…

Operator Algebras · Mathematics 2007-05-23 Erik Christensen , Cristina Ivan

We present theoretical properties of the space of metric pairs equipped with the Gromov--Hausdorff distance. First, we establish the classical metric separability and the geometric geodesicity of this space. Second, we prove an…

Metric Geometry · Mathematics 2026-02-06 Andrés Ahumada Gómez , Mauricio Che , Manuel Cuerno

We show that the algebra A of a commutative unital spectral triple (A,H,D) satisfying several additional conditions, slightly stronger than those proposed by Connes, is the algebra of smooth functions on a compact spin manifold.

Operator Algebras · Mathematics 2008-02-04 Adam Rennie , Joseph C. Varilly

Let G be a finitely generated discrete group. The standard spectral triple on the group C*-algebra C*(G) is shown to admit the quantum group of orientation preserving isometries. This leads to new examples of compact quantum groups. In…

Operator Algebras · Mathematics 2015-05-18 Jyotishman Bhowmick , Adam Skalski

We study the triple $(G,\pi,\prs)$ where $G$ is a connected and simply connected Lie group, $\pi$ and $\prs$ are, respectively, a multiplicative Poisson tensor and a left invariant Riemannian metric on $G$ such that the necessary…

Differential Geometry · Mathematics 2009-06-17 Amine Bahayou , Mohamed Boucetta

We construct quantum metric structures on unital AF algebras with a faithful tracial state, and prove that for such metrics, AF algebras are limits of their defining inductive sequences of finite dimensional C*-algebras for the quantum…

Operator Algebras · Mathematics 2016-05-18 Konrad Aguilar , Frederic Latremoliere

We construct spectral triples for the C^*-algebra of continuous functions on the quantum SU(2) group and the quantum sphere. There has been various approaches towards building a calculus on quantum spaces, but there seems to be very few…

Quantum Algebra · Mathematics 2009-11-07 Partha Sarathi Chakraborty , Arupkumar Pal

We study adjointable, bounded operators on the direct sum of two copies of the standard Hilbert C*-module over a unital C*-algebra A that are given by upper triangular 2 by 2 operator matrices. Using the definition of A-Fredholm and…

Functional Analysis · Mathematics 2020-12-08 Stefan Ivkovic

A structure theorem for bounded-below modules over the subalgebra A(1) of the mod 2 Steenrod algebra generated by Sq^1, Sq^2 is proved; this is applied to prove a classification theorem for a family of indecomposable A(1)-modules. The…

Algebraic Topology · Mathematics 2014-12-30 Geoffrey Powell

We describe the construction of theta summable and finitely summable spectral triples associated to Mumford curves and some classes of higher dimensional buildings. The finitely summable case is constructed by considering the stabilization…

Quantum Algebra · Mathematics 2007-05-23 Gunther Cornelissen , Matilde Marcolli , Kamran Reihani , Alina Vdovina

Let $(M,g)$ be a surface with Riemannian metric and curved conic singularities. More precisely, a neighbourhood of a singularity is isometric to $(0,1)\times S^1$ with metric $g_{\text{conic}}=dr^2+f(r)^2d\theta^2, r\in(0,1)$. We study the…

Differential Geometry · Mathematics 2017-11-03 Asilya Suleymanova

In order to study the Hochschild cohomology of triangular algebras $\mathcal T$, we construct a spectral sequence, whose terms are parametrized by the length of the trajectories of the quiver associated with $\mathcal T$, and which…

Rings and Algebras · Mathematics 2007-05-23 Sophie Dourlens

We generalize the notion of a continuous field of C*-algebras to that of Hilbert C*-bimodules. Given a partially ordered set $P$ and a monotonically non-decreasing family of ternary rings of operators (TROs) assigned to the points of $P$,…

Operator Algebras · Mathematics 2026-03-25 Vladimir Manuilov

We give a construction of an odd spectral triple on the Cuntz algebra $O_{N}$, whose $K$-homology class generates the odd $K$-homology group $K^1(O_{N})$. Using a metric measure space structure on the Cuntz-Renault groupoid, we introduce a…

Operator Algebras · Mathematics 2018-08-17 Magnus Goffeng , Bram Mesland

Two spectral triples are introduced for a class of fractals in R^n. The definitions of noncommutative Hausdorff dimension and noncommutative tangential dimensions, as well as the corresponding Hausdorff and Hausdorff-Besicovitch functionals…

Operator Algebras · Mathematics 2009-09-29 Daniele Guido , Tommaso Isola

On a discrete group G a length function may implement a spectral triple on the reduced group C*-algebra. Following A. Connes, the Dirac operator of the triple then can induce a metric on the state space of reduced group C*-algebra. Recent…

Operator Algebras · Mathematics 2007-05-23 Cristina Antonescu , Erik Christensen
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