Block Diagonalization in Banach Algebras
by
Robin Harte
Trinity College, Dublin, Ireland

``Reduction" of linear operators is effected by commuting projections; the spectrum of the operator is then the union of the spectra of its range and null space restrictions. Disjointness of these partial spectra implies that the projection ``double commutes" with the operator, which in turn can be recognized as a curious kind of ``exactness". Variants of this exactness correspond to various kinds of disjointness between the partial spectra.

Date received: March 29, 1999

Copyright © 1999 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cacw-15.