Outdated Archival Version

These pages are not updated anymore. They reflect the state of 20 August 2005. For the current production of this journal, please refer to http://www.math.psu.edu/era/.

This journal is archived by the American Mathematical Society. The master copy is available at http://www.ams.org/era/

We find canonical decompositions for finitely presented groups which essentially specialise to the classical JSJ-decomposition when restricted to the fundamental groups of Haken manifolds. The decompositions that we obtain are invariant under automorphisms of the group. A crucial new ingredient is the concept of a regular neighbourhood of a family of almost invariant subsets of a group. An almost invariant set is an analogue of an immersion.

Copyright 2002 American Mathematical Society

TeX source (22.4K)
DVI (28.5K)
PostScript (94.0K)

Article Info

• ERA Amer. Math. Soc. 08 (2002), pp. 29-34
• Publisher Identifier: S 1079-6762(02)00101-4
• 2000 Mathematics Subject Classification. Primary 53D05; Secondary 53D20, 32S60, 52B20
• Key words and phrases. Symplectic quasifolds, moment mapping, stratified spaces, convex polytopes
• Received by editors June 16, 2002
• Posted on September 17, 2002
• Communicated by Frances Kirwan
• Comments (When Available)

Fiammetta Battaglia

Dipartimento di Matematica Applicata ``G. Sansone'', Via S. Marta 3, 50139 Firenze, Italy

E-mail address: fiamma@dma.unifi.it

Elisa Prato

Laboratoire Dieudonné, Université de Nice, Parc Valrose, 06108 Nice Cedex 2, France

E-mail address: elisa@alum.mit.edu

The first author was partially supported by MIUR project Proprietŕ Geometriche delle Varietŕ Reali e Complesse, by GNSAGA (CNR), and by EDGE (EC FP5 Contract no. HPRN-CT-2000-00101).