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The notion of a K\"ahler structure for a differential calculus was recently introduced by the second author as a framework in which to study the noncommutative geometry of the quantum flag manifolds. It was subsequently shown that any…

Quantum Algebra · Mathematics 2020-07-30 Biswarup Das , Réamonn Ó Buachalla , Petr Somberg

In this paper we classify filiform associative algebras of degree $k$ over a field of characteristic zero. Moreover, we also classify naturally graded complex filiform and quasi-filiform nilpotent associative algebras which are described by…

Rings and Algebras · Mathematics 2018-08-21 Ikboljon A. Karimjanov , Manuel Ladra

We consider a smooth submanifold $N$ with a smooth boundary in an ambient closed manifold $M$ and assign a spectral invariant $c(\alpha,H)$ to every singular homological class $\alpha\in H_*(N)$ and a Hamiltonian $H$ defined on the…

Symplectic Geometry · Mathematics 2019-01-24 Jelena Katić , Darko Milinković , Jovana Nikolić

We show that the noncommutative spheres of Connes and Landi are quantum homogeneous spaces for certain compact quantum groups. We give a general construction of homogeneous spaces which support noncommutative spin geometries.

Quantum Algebra · Mathematics 2011-07-19 Joseph C. Varilly

A notion of fundamental group of spectral triples has been introduced. The notion uses a noncommutative analogue of unramified coverings. It was shown that in commutative case this fundamental group is a profinite completion of fundamental…

K-Theory and Homology · Mathematics 2007-05-23 Petr R. Ivankov , Nickolay P. Ivankov

We give some graph theoretical formulas for the trace $Tr_k(\mathbb {T})$ of a tensor $\mathbb {T}$ which do not involve the differential operators and auxiliary matrix. As applications of these trace formulas in the study of the spectra of…

Spectral Theory · Mathematics 2013-07-23 Jia-Yu Shao , Liqun Qi , Shenglong Hu

We use a Heegaard splitting of the topological 3-sphere as a guiding principle to construct a family of its noncommutative deformations. The main technical point is an identification of the universal C*-algebras defining our quantum…

K-Theory and Homology · Mathematics 2009-09-29 Paul Baum , Piotr M. Hajac , Rainer Matthes , Wojciech Szymanski

We offer a short proof of Connes' Hochschild class of the Chern character formula for non-unital semifinite spectral triples. The proof is simple due to its reliance on the authors' extensive work on a refined version of the local index…

K-Theory and Homology · Mathematics 2018-05-02 Alan L. Carey , A. Rennie

Commutative K-theory, a cohomology theory built from spaces of commuting matrices, has been explored in recent work of Adem, G\'{o}mez, Gritschacher, Lind, and Tillman. In this article, we use unstable methods to construct explicit…

Algebraic Topology · Mathematics 2019-06-04 Daniel A. Ramras , Bernardo Villarreal

We show that sheet closures appear as associated varieties of affine vertex algebras. Further, we give new examples of non-admissible affine vertex algebras whose associated variety is contained in the nilpotent cone. We also prove some…

Representation Theory · Mathematics 2019-03-14 Tomoyuki Arakawa , Anne Moreau

We introduce a divisibility-type condition for directed graphs that is necessary for $\mathcal{Z}$-stability of the corresponding graph $C^*$-algebra. We prove that this condition is sufficient if either the graph $E$ has no cycles or the…

Operator Algebras · Mathematics 2025-11-05 Gregory Faurot

Within the framework of Connes' noncommutative geometry, we define and study globally non-trivial (or topologically non-trivial) almost-commutative manifolds. In particular, we focus on those almost-commutative manifolds that lead to a…

Mathematical Physics · Physics 2014-11-13 Jord Boeijink , Koen van den Dungen

An orientation of a graph is semi-transitive if it is acyclic, and for any directed path $v_0\rightarrow v_1\rightarrow \cdots\rightarrow v_k$ either there is no edge between $v_0$ and $v_k$, or $v_i\rightarrow v_j$ is an edge for all…

Combinatorics · Mathematics 2019-03-08 Sergey Kitaev , Akira Saito

The regular embeddings of complete bipartite graphs $K_{n,n}$ in orientable surfaces are classified and enumerated, and their automorphism groups and combinatorial properties are determined. The method depends on earlier classifications in…

Combinatorics · Mathematics 2014-02-26 Gareth A. Jones

We discuss generalizations of the notion of i) the group of unitary elements of a (real or complex) finite dimensional C*-algebra, ii) gauge transformations and iii) (real) automorphisms, in the framework of compact quantum group theory and…

Quantum Algebra · Mathematics 2014-10-13 Jyotishman Bhowmick , Francesco D'Andrea , Biswarup Das , Ludwik Dabrowski

We classify non-algebraic compact K\"ahler threefolds admitting an endomorphism $f: X \to X$ of degree at least two.

Algebraic Geometry · Mathematics 2017-11-10 Andreas Höring , Thomas Peternell

In this article, we give an explicit construction of the simple modules for both non-degenerate and degenerate cyclotomic Hecke-Clifford superalgebras over an algebraically closed field of characteristic not equal to $2$ under certain…

Representation Theory · Mathematics 2025-03-27 Lei Shi , Jinkui Wan

This paper concerns fractional $K_s$-decompositions of multipartite graphs. For integers $r\ge s\ge 3$, we consider balanced $r$-partite graphs $G$ on $rn$ vertices. We establish necessary conditions for $G$ to admit a fractional…

Combinatorics · Mathematics 2026-04-29 Tao Feng , Hengrui Liu , Shikang Yu

We show how to construct a non-2-colorable k-uniform hypergraph with (2^(1 + o(1)))^k edges. By the duality of hypergraphs and monotone k-CNF-formulas this gives an unsatisfiable monotone k-CNF with (2^(1 + o(1)))^k clauses

Discrete Mathematics · Computer Science 2009-11-05 Heidi Gebauer

This research notes is intended to provide a quick introduction to the subject. We expose a K-theoretic approach to study group C*-algebras: started in the elementary part, with one example of description of the structure of C*-algebras of…

K-Theory and Homology · Mathematics 2014-06-09 Do Ngoc Diep
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