The Laplacian MASA in a free group factor Academic Article uri icon


  • The Laplacian (or radial) masa in a free group factor is generated by the sum of the generators and their inverses. We show that such a masa B is strongly singular and has Popa invariant δ(B) = 1. This is achieved by proving that the conditional expectation double struct E signBonto B is an asymptotic homomorphism. We also obtain similar results for the free product of discrete groups, each of which contains an element of infinite order.

author list (cited authors)

  • Sinclair, A. M., & Smith, R. R.

citation count

  • 8

complete list of authors

  • Sinclair, Allan||Smith, Roger

publication date

  • October 2002