We prove that uniform Roe C*-algebras C _u ~* X associated to some expander graphs X coming from discrete groups with property (?.,) are not K-exact. In particular, we show that this is the case for the expander obtained as Cayley graphs of a sequence of alternating groups (with appropriately chosen generating sets).
展开▼
机译：我们证明，与来自具有属性（？，）的离散组的一些扩展图X相关的统一Roe C *代数C_u〜* X不是K精确的。尤其是，我们证明了这种情况，对于以交替组序列（具有适当选择的生成集）的Cayley图作为扩展器获得的扩展器就是这种情况。
展开▼
