The extension 6 is actually unique (see below). (We recall that a connected Lie group is called simple if it is nonabelian and has no proper normal subgroup of dimension >0. The lowest dimension of aâ€¦ (More)

The operator A(D) is called the radial component of D. Many special cases have been considered (see e.g. [l, Â§2], [4, Â§5], [5, Â§3], [7, Â§7], [8, Chapter IV, Â§Â§3-5]). Suppose now dv (resp. dw) is aâ€¦ (More)

A braided n-path is a set of Â« paths ct(t) in R 3 (i = 1 , . . . , n) satisfying (1) c,(0 = (*,(>), MO, 0> ' i < * < r2, c ^ ) = Pâ€ž C/(r2) e { & , . . ,Ã”â€ž}(2) The paths do not intersect. Two braidedâ€¦ (More)

Mostow has also conjectured the following: MOSTOW CONJECTURE. A solvmanifold is a vector bundle over a compact solvmanifold. In this paper we will announce results that yield a new proof of Theorem 1â€¦ (More)

Proceedings of the National Academy of Sciencesâ€¦

1978

The proof of the well-known conjecture that lattices in groups of R-rank greater than 1 are arithmetic has raised speculation about the existence of nonarithmetic lattices in the R-rank 1 groupâ€¦ (More)

Proceedings of the National Academy of Sciencesâ€¦

1996

This paper presents a brief survey of the idea of symmetry in mathematics, as exemplified by some particular developments in algebra, differential equations, topology, and number theory.

Proceedings of the National Academy of Sciencesâ€¦

1973

The finite generation of the ring of invariants of a special class of unipotent groups is established-namely, unipotent radicals of parabolic subgroups.