Volume 118, Issue 2 – September 1983

## Solution of the similarity problem for cyclic representations of $C^\ast$-algebras

Pages 215-240 by Uffe Haagerup

## Unramified class field theory of arithmetical surfaces

Pages 241-275 by Kazuya Kato, Shuji Saito

## Horocycle flows, joinings and rigidity of products

Pages 277-313 by Marina Ratner

## Derivatives of analytic families of Banach spaces

Pages 315-347 by Richard Rochberg, Guido Weiss

## Sharp constants in the Hardy-Littlewood-Sobolev and related inequalities

Pages 349-374 by Elliot H. Lieb

## On the torsion in $K_2$ of local fields

Pages 375-381 by Alexander S. Merkurjev