作者：Bourgain, Jean; Gamburd, Alex
作者单位：Institute for Advanced Study - USA; University of California System; University of California Santa Cruz; University of California System; University of California Santa Cruz
摘要：We prove the spectral gap property for free subgroups of SU(2) generated by elements satisfying a noncommutative diophantine property, in particular for free subgroups generated by elements with algebraic entries.
作者：Akhmedov, Anar; Park, B. Doug
作者单位：University System of Georgia; Georgia Institute of Technology; University of Waterloo
摘要：Let M be either CP2#3 (CP) over bar (2) or 3CP(2)#5 (CP) over bar (2). We construct the first example of a simply-connected irreducible symplectic 4-manifold that is homeomorphic but not diffeomorphic to M.
