Browsing by Author "Skalski, Adam"

Now showing 1 - 4 of 4
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    Classification of idempotent states on the compact quantum groups Uq(2), SUq(2), and SOq(3)
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach, 2009) Franz, Uwe; Skalski, Adam; Tomatsu, Reiji
    We give a simple characterisation of those idempotent states on compact quantum groups which arise as Haar states on quantum subgroups, show that all idempotent states on quantum groups Uq(2), SUq(2), and SOq(3) (q 2 (−1, 0) [ (0, 1]) arise in this manner and list the idempotent states on compact quantum semigroups U0(2), SU0(2), and SO0(3). In the Appendix we provide a simple proof of coamenability of the deformations of classical compact Lie groups.
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    Contractive idempotents on locally compact quantum groups
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach, 2012) Neufang, Matthias; Salmi, Pekka; Skalski, Adam; Spronk, Nico
    general form of contractive idempotent functionals on coamenable locally compact quantum groups is obtained, generalising the result of Greenleaf on contractive measures on locally compact groups. The image of a convolution operator associated to a contractive idempotent is shown to be a ternary ring of operators. As a consequence a one-to-one correspondence between contractive idempotents and a certain class of ternary rings of operators is established.
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    Noncommutative topological entropy of endomorphisms of Cuntz algebras
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach, 2008) Skalski, Adam; Zacharias, Joachim
    Noncommutative topological entropy estimates are obtained for ‘finite range’ endomorphisms of Cuntz algebras, generalising known results for the canonical shift endomorphisms. Exact values are computed for a class of polynomial endomorphisms related to branching function systems introduced and studied by Bratteli, Jorgensen and Kawamura.
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    Quantum Groups - Algebra, Analysis and Category Theory (hybrid meeting)
    (Zürich : EMS Publ. House, 2021) Neshveyev, Sergey; Nikshych, Dmitri; Skalski, Adam
    The meeting was devoted to discussing the state of the art of different branches of tensor categories and quantum groups, with emphasis on the exchange of ideas between the purely algebraic and operator algebraic sides of these theories.