Conditions involving closed range of multipliers on general Banach algebras are studied. Numerous conditions equivalent to a splitting A = TA ⊕ kerT are listed, for a multiplier T defined on the Banach algebra A. For instance, it is shown that TA ⊕ kerT = A if and only if there is a commuting operator S for which T = TST and S = STS, that this is the case if and only if such S may be taken to be a multiplier, and that these conditions are also equivalent to the existence of a factorization T = PB, where P is an idempotent and B an invertible multiplier. The latter condition establishes a connection to a famous problem of harmonic analysis.
@article{bwmeta1.element.bwnjournal-article-smv107i2p127bwm, author = {K. Laursen and M. Mbekhta}, title = {Closed range multipliers and generalized inverses}, journal = {Studia Mathematica}, volume = {104}, year = {1993}, pages = {127-135}, zbl = {0812.47031}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-smv107i2p127bwm} }
Laursen, K.; Mbekhta, M. Closed range multipliers and generalized inverses. Studia Mathematica, Tome 104 (1993) pp. 127-135. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-smv107i2p127bwm/
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