Geodesic
A Geometric Characterization of Nonnegative Bands
Canadian mathematical bulletin, Tome 47 (2004) no. 2, pp. 257-263

Voir la notice de l'article provenant de la source Cambridge University Press

A band is a semigroup of idempotent operators. A nonnegative band $\mathcal{S}$ in $B({{L}^{2}}(X))$ having at least one element of finite rank and with rank $(S)\,>\,1$ for all $S$ in $\mathcal{S}$ is known to have a special kind of common invariant subspace which is termed a standard subspace (defined below).Such bands are called decomposable. Decomposability has helped to understand the structure of nonnegative bands with constant finite rank. In this paper, a geometric characterization of maximal, rank-one, indecomposable nonnegative bands is obtained which facilitates the understanding of their geometric structure.
DOI : 10.4153/CMB-2004-025-0
Mots-clés : 47D03, 47A15 
Marwaha, Alka. A Geometric Characterization of Nonnegative Bands. Canadian mathematical bulletin, Tome 47 (2004) no. 2, pp. 257-263. doi: 10.4153/CMB-2004-025-0
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