Bourbaki

Corollary 2

Tag 02T6, permanent. Cite it as [Bourbaki, Tag 02T6].

Théories spectrales, chapter III, § 4. Perturbations dans les espaces de Banach

The function u↦u\mapsto dim Coker(uu) is locally constant on the set M(E;F)\mathscr{M}(E; F) of strict injective morphisms of E into F.

Indeed, one has dim Coker(uu) == ind(uu) for u∈M(E;F)u\in \mathscr{M}(E; F).

Bourbaki sets the proof directly after the statement, and the corpus does not separate them, so what is above is the statement and its proof together.

Cited by

Nothing.

Cites

Nothing.

Machine translation of the English, by gpt-5.4, against glossary version 34. Not checked by a person.