-
作者：Kenig, Carlos E.; Sjostrand, Johannes; Uhlmann, Gunther
摘要：In this paper we improve an earlier result by Bukhgeim and Uhlmann [1] by showing that in dimension n >= 3, the knowledge of the Cauchy data for the Schrodinger equation measured on possibly very small subsets of the boundary determines uniquely the potential. We follow the general strategy of [1] but use a richer set of solutions to the Dirichlet problem. This implies a similar result for the problem of Electrical Impedance Tomography which consists in determining the conductivity of a body b...
-
作者：Kaloshin, Vadim Yu.; Hunt, Brian R.
摘要：For diffeomorphisms of smooth compact finite-dimensional manifolds, we consider the problem of how fast the number of periodic points with period n grows as a function of n. In many familiar cases (e.g., Anosov systems) the growth is exponential, but, arbitrarily fast growth is possible; in fact, the first author has shown that arbitrarily fast growth is topologically (Baire) generic for C-2 or smoother diffeomorphisms. In the present work we show that, by contrast, for a measure-theoretic not...
-
作者：Nikolov, Nikolay; Segal, Dan
摘要：We prove that in every finitely generated profinite group, every subgroup of finite index is open; this implies that the topology on such groups is determined by the algebraic structure. This is deduced from the main result about finite groups: let w be a 'locally finite' group word and d is an element of N. Then there exists f = f (w, d) such that in every d-generator finite group G, every element of the verbal subgroup w(G) is equal to a product of f w-values. An analogous theorem is proved ...
-
作者：Bishop, Christopher J.
摘要：It is well known that not every orientation-preserving homeomorphisin of the circle to itself is a conformal welding, but in this paper we prove several results which state that every homeomorphism is almost a welding in a precise way. The proofs are based on Koebe's circle domain theorem. We also give a new proof of the well known fact that quasisymmetric maps are conformal weldings.
-
作者：Schwede, Stefan
-
作者：Bridgeland, Tom
-
作者：Bromberg, K.
摘要：We prove the Bers density conjecture for singly degenerate Kleinian surface groups without parabolics.
-
作者：Ammann, Bernd; Lauter, Robert; Nistor, Victor
摘要：We define and study an algebra Psi(infinity)(1,0,nu)(M-0) of pseudodifferential operators canonically associated to a noncompact, Riemannian manifold M-0 whose geometry at infinity is described by a Lie algebra of vector fields V on a compactification M of M-0 to a compact manifold with corners. We show that the basic properties of the usual algebra of pseudodifferential operators on a compact manifold extend to Psi(infinity)(1,0,nu)(M-0) . We also consider the algebra Diff nu*(M-0) of differe...
-
作者：Barraud, Jean-Francois; Cornea, Octav
摘要：For a transversal pair of closed Lagrangian submanifolds L, L ' of a symplectic manifold M such that pi(1), (L) = pi(1) (L ') = 0 = C-1 vertical bar pi(2(M)) = omega vertical bar(pi 2(M)) and for a generic almost complex structure J, we construct an invariant with a high homotopical content which consists in the pages of order >= 2 of a spectral sequence whose differentials provide an algebraic measure of the high-dimensional moduli spaces of pseudo-holomorpic strips of finite energy that join...
-
作者：Breuillard, E.; Gelander, T.
摘要：Let k be a local field, and Gamma <= GL(n)(k) a linear group over k. We prove that 17 contains either a relatively open solvable subgroup or a relatively dense free subgroup. This result has applications in dynamics, Riemannian foliations and profinite groups.
