1,824 research outputs found

    Dirac-Jacobi Bundles

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    We show that a suitable notion of Dirac-Jacobi structure on a generic line bundle LL, is provided by Dirac structures in the omni-Lie algebroid of LL. Dirac-Jacobi structures on line bundles generalize Wade's E1(M)\mathcal E^1 (M)-Dirac structures and unify generic (i.e.~non-necessarily coorientable) precontact distributions, Dirac structures and local Lie algebras with one dimensional fibers in the sense of Kirillov (in particular, Jacobi structures in the sense of Lichnerowicz). We study the main properties of Dirac-Jacobi structures and prove that integrable Dirac-Jacobi structures on line-bundles integrate to (non-necessarily coorientable) precontact groupoids. This puts in a conceptual framework several results already available in literature for E1(M)\mathcal E^1 (M)-Dirac structures.Comment: v6: 55 pages, corrected some minor mistakes, final version, to appear in J. Sympl. Geom, 16 (2018

    A criterion for existence of right-induced model structures

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    Suppose that F:N→MF: \mathcal{N} \to \mathcal{M} is a functor whose target is a Quillen model category. We give a succinct sufficient condition for the existence of the right-induced model category structure on N\mathcal{N} in the case when FF admits both adjoints. We give several examples, including change-of-rings, operad-like structures, and anti-involutive structures on infinity categories. For the last of these, we explore anti-involutive structures for several different models of (∞,1)(\infty, 1)-categories, and show that known Quillen equivalences between base model categories lift to equivalences

    Holomorphic geometric models for representations of C∗C^*-algebras

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    Representations of C∗C^*-algebras are realized on section spaces of holomorphic homogeneous vector bundles. The corresponding section spaces are investigated by means of a new notion of reproducing kernel, suitable for dealing with involutive diffeomorphisms defined on the base spaces of the bundles. Applications of this technique to dilation theory of completely positive maps are explored and the critical role of complexified homogeneous spaces in connection with the Stinespring dilations is pointed out. The general results are further illustrated by a discussion of several specific topics, including similarity orbits of representations of amenable Banach algebras, similarity orbits of conditional expectations, geometric models of representations of Cuntz algebras, the relationship to endomorphisms of B(H){\mathcal B}({\mathcal H}), and non-commutative stochastic analysis.Comment: 45 page
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