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Related papers: K-theoretic Poirier-Reutenauer bialgebra

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In this paper, we apply quantitative operator K-theory to develop an algorithm for computing K-theory for the class of filtered C *-algebras with asymptotic finite nuclear decomposition. As a consequence, we prove the K{\"u}nneth formula…

Operator Algebras · Mathematics 2016-09-14 Hervé Oyono-Oyono , Guoliang Yu

We compute the genus of a rational quadratic form in terms of the K-theory of a C*-algebra attached to the adelic orthogonal group of the form. As a corollary, one gets a higher composition law for the rational quadratic forms. As an…

Number Theory · Mathematics 2019-10-09 Igor Nikolaev

KK-theory is a bivariant and homotopy-invariant functor on $C^*$-algebras that combines K-theory and K-homology. KK-groups form the morphisms in a triangulated category. Spanier-Whitehead K-Duality intertwines the homological with the…

Operator Algebras · Mathematics 2026-01-08 Ulrich Pennig , Taro Sogabe

We show that the real K-theory spectrum KO is Anderson self-dual using the method previously employed in the second author's calculation of the Anderson dual of Tmf. Indeed the current work can be considered as a lower chromatic version of…

Algebraic Topology · Mathematics 2015-12-09 Drew Heard , Vesna Stojanoska

We classify quantum analogues of actions of finite subgroups G of SL_2(k) on commutative polynomial rings k[u,v]. More precisely, we produce a classification of pairs (H,R), where H is a finite dimensional Hopf algebra that acts inner…

Rings and Algebras · Mathematics 2014-07-03 Kenneth Chan , Ellen Kirkman , Chelsea Walton , James Zhang

We study several duality isomorphisms between equivariant bivariant K-theory groups, generalising Kasparov's first and second Poincare duality isomorphisms. We use the first duality to define an equivariant generalisation of Lefschetz…

K-Theory and Homology · Mathematics 2011-05-03 Heath Emerson , Ralf Meyer

We introduce a new morphism between algebraic and hermitian K-theory. The topological analog is the Adams operation in real K-theory. From this morphism, we deduce a lower bound for the higher algebraic K-theory of a ring A in terms of the…

K-Theory and Homology · Mathematics 2016-09-07 Max Karoubi

We introduce a new version $kk^{\rm alg}$ of bivariant $K$-theory that is defined on the category of all locally convex algebras. A motivating example is the Weyl algebra $W$, i.e. the algebra generated by two elements satisfying the…

K-Theory and Homology · Mathematics 2007-05-23 Joachim Cuntz

For T an abelian compact Lie group, we give a description of T-equivariant K-theory with complex coefficients in terms of equivariant cohomology. In the appendix we give applications of this by extending results of Chang-Skjelbred and…

Algebraic Topology · Mathematics 2009-03-10 Ioanid Rosu , Allen Knutson

We prove that the standard K\"unneth map in periodic cyclic homology of differential Z/2-graded algebras is compatible with a generalization of the Hodge filtration and explain how this result is related to various Thom-Sebastiani type…

Algebraic Geometry · Mathematics 2014-03-03 Dmytro Shklyarov

We prove several results showing that the algebraic $K$-theory of valuation rings behave as though such rings were regular Noetherian, in particular an analogue of the Geisser--Levine theorem. We also give some new proofs of known results…

K-Theory and Homology · Mathematics 2018-10-30 Shane Kelly , Matthew Morrow

We compute the groupoid homology for the ample groupoids associated with algebraic actions from rings of algebraic integers and integral dynamics. We derive results for the homology of the topological full groups associated with rings of…

Operator Algebras · Mathematics 2024-07-03 Chris Bruce , Yosuke Kubota , Takuya Takeishi

It was shown by Rordam and the second named author that a countable group G admits an action on a compact space such that the crossed product is a Kirchberg algebra if, and only if, G is exact and non-amenable. This construction allows a…

Operator Algebras · Mathematics 2011-11-01 G. A. Elliott , A. Sierakowski

Realizing the possibility suggested by Hardouin [6], we show that her own Picard-Vessiot Theory for iterative $q$-difference rings is covered by the (consequently, more general) framework, settled by Amano and Masuoka [2], of artinian…

Quantum Algebra · Mathematics 2013-03-20 Akira Masuoka , Makoto Yanagawa

We prove an identity relating the product of two opposite Schubert varieties in the (equivariant) quantum K-theory ring of a cominuscule flag variety to the minimal degree of a rational curve connecting the Schubert varieties. We deduce…

Algebraic Geometry · Mathematics 2018-01-31 Anders Skovsted Buch , Sjuvon Chung

We introduce the notion of a homotopy of product systems, and show that the Cuntz-Nica-Pimsner algebras of homotopic product systems over N^k have isomorphic K-theory. As an application, we give a new proof that the K-theory of a 2-graph…

Operator Algebras · Mathematics 2024-08-16 James Fletcher , Elizabeth Gillaspy , Aidan Sims

We prove a twisting theorem for nodal classes in permutation-equivariant quantum $K$-theory, and combine it with existing theorems of Givental to obtain a twisting result for general characteristic classes of the virtual tangent bundle.…

Algebraic Geometry · Mathematics 2021-01-27 Irit Huq-Kuruvilla

We give a new formula for the antipode of the algebra of rooted trees, directly in terms of the bialgebra structure. The equivalence, proved in this paper, among the three available formulae for the antipode, reflects the equivalence among…

High Energy Physics - Theory · Physics 2009-10-31 Hector Figueroa , Jose M. Gracia-Bondia

The Minkowski spacetime quantum Clifford algebra structure associated with the conformal group and the Clifford-Hopf alternative k-deformed quantum Poincare algebra is investigated in the Atiyah-Bott-Shapiro mod 8 theorem context. The…

Mathematical Physics · Physics 2010-09-28 Roldao da Rocha , Alex E. Bernardini , Jayme Vaz

We consider the homology theory of \'etale groupoids introduced by Crainic and Moerdijk, with particular interest to groupoids arising from topological dynamical systems. We prove a K\"unneth formula for products of groupoids and a…

K-Theory and Homology · Mathematics 2025-08-19 Valerio Proietti , Makoto Yamashita