• Classification of idempotent states on the compact quantum groups Uq(2), SUq(2) and SOq(3) 

      [OWP-2009-08] Franz, Uwe; Skalski, Adam; Tomatsu, Reiji (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-02)
      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 $U_q(2)$, $SU_q(2)$, and $SO_q(3) ...
    • Contractive Idempotents on Locally Compact Quantum Groups 

      [OWP-2012-19] Neufang, Matthias; Salmi, Pekka; Skalski, Adam; Spronk, Nico (Mathematisches Forschungsinstitut Oberwolfach, 2012)
      A 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 ...
    • Noncommutative topological entropy of endomorphismus of Cuntz Algebras 

      [OWP-2008-12] Skalski, Adam; Zacharias, Joachim (Mathematisches Forschungsinstitut Oberwolfach, 2008-03-16)
      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 ...