作者：Hofer, H; Wysocki, K; Zehnder, E
摘要：We show that a Hamiltonian flow on a three-dimensional strictly convex energy surface S subset of R-4 possesses a global surface of section of disc type. It follows, in particular, that the number of its periodic orbits is either 2 or infinity, by a recent result of J. Franks on area-preserving homeomorphisms of an open annulus in the plane. The construction of this surface of section is based on partial differential equations of Cauchy-Riemann type for maps from punctured Riemann surfaces int...
作者：Friedman, HM
摘要：We begin by presenting a new kind of finite counting theorem which asserts that any function on vectors of natural numbers has few low values over finite sets of arbitrary size (Theorems 0.1 and 0.2 from the introduction). This estimate on the low values therein called regressive values) is linear in the sizes of the finite sets. This basic counting theorem is extended to systems of finite functions, where it is shown that every system which is decreasing tin appropriate senses) includes funct...
作者：Burago, D; Ferleger, S; Kononenko, A
作者：Friedlander, J; Iwaniec, H
作者：Epstein, CL
摘要：We consider the Szego projector and the partial inverse for the square(b)-operator defined by a strictly pseudoconvex CR-structure on a compact manifold. In particular we study the dependence on the CR-structure in the construction of Beals and Greiner of an approximate projector and partial inverse for square(b). Parametrices for some operators introduced in [Ep] are constructed. This entails the analysis of the inverses for certain classes of convolution operators on the Heisenberg group.
