American Journal of Mathematics articles from April 1995

American Journal of Mathematics archives from April 1995

Characterization of the bidisc by its automorphism group.
April 1, 1995... 1. Introduction. The purpose of this paper is to give a characterization of the bidisc [[delta].sub.2] = [Mathematical Expression Omitted] by its automorphism group (i.e. group of biholomorphisms). Theorem. Let D be a bounded domain in...

A symbolic proof of a theorem of Margulis on geodesic arcs on negatively curved manifolds.
April 1, 1995... Introduction. Let V be a compact manifold with negative sectional curvatures and, given two points x, y [element of] V, we denote by [rho] xy(t) the number of geodesic segments with length at most t > 0, which start at the point x and finish at...

Geometric and arithmetic aspects of Pn minus hyperplanes.
April 1, 1995... 1. Introduction. A complex space M is called Brody hyperbolic if every holomorphic curve f : C [right arrow] M is constant. Recent studies suggest that the hyperbolicity of complex space M is related to the finiteness of the number of rational...

Primitive ideal spaces of discrete rational nilpotent groups.
April 1, 1995... 1. Introduction. In what follows, let g[.sub.Q] be a nilpotent Lie algebra with rational structure constants; i.e., g[.sub.Q] has a basis {[X.sub.1],...,[X.sub.k]} of vectors such that [Mathematical Experession Omitted] with all...

Multipliers and lacunary sets in non-amenable groups.
April 1, 1995... 0. Introduction. Let G be a discrete group. Let [lambda] : G [right arrow] B([l.sub.2] (G), [l.sub.2] (G)) be the left regular representation. A function [Laplace operational symbol] : G [right arrow] C is called a completely bounded...

Noncrossed products and nonabelian crossed products over Q(T) and Q((T)).
April 1, 1995... 1. Introduction. The primary result of this paper is a construction of noncrossed product division algebras whose centers are rational function fields k(t) and Laurent series fields k((t)) over number fields k. We also show that when k = Q, the...

Bezout estimate for entire holomorphic maps and their Jacobians.
April 1, 1995... 1. Introduction. Given a holomorphic map f: [C.sup.n] [right arrow] [C.sup.n] with dim [f.sup.-1](0) = O. It is a very interesting problem to understand the counting functions [N.sub.f](r) and [N.sub.f](r) for large r. When f is algebraic,...

Polynomial hulls of rectifiable curves.
April 1, 1995... The material in this paper grew out of an attempt to generalize some work of Alexander on the structure of polynomial hulls of 1-rectifiable subsets of [C.sup.n.] Specifically, Alexander has shown that if X C [C.sup.n] is a connected compact...

An abstract characterization of the Igusa curves.
April 1, 1995... Let K be a field of characteristic p > 0, let [K.sup.alg] be an algebraic closure of K, and let [K.sup.sep] be the separable closure of K in [K.sup.alg]. Let E be an ordinary elliptic curve over K. Then the group of [p.sup.n]-torsion points of...

The Haagerup invariant for von Neumann algebras.
April 1, 1995... 1. Introduction. There are many versions of the approximation property for a Banach space [chi] but all have a common theme: there exists a net {T[alpha]: [chi] [right arrow] [chi]}[alpha][element of]A of finite rank maps converging to I in an...

On the convergence of the adelic zeta functions associated to irreducible regular prehomogeneous vector spaces.
April 1, 1995... Introduction. Let (G, X) be an irreducible regular prehomogeneous vector space defined over an algebraic number field k. D denotes the derived group of G. X is an affine n-space [Mathematical Expressions Omitted] is the relative invariant....

Involutive structures on compact manifolds.
April 1, 1995... Introduction. Involutive structures (also called formally integrable structures) include and generalize the de Rham and Dolbeault complexes. Both local and global questions are of interest. One class of local problems is that of...

Norm estimates for iterated commutators on the Bergman spaces of the unit ball.
April 1, 1995... Introduction. We study the iterated commutators of the Bergman projection and the multiplication by measurable functions (called the symbols). Unlike the commutators, the iterated commutators are no longer depending linearly on their symbols....