Bourbaki

Remark 3

Tag 024V, permanent. Cite it as [Bourbaki, Tag 024V].

Théories spectrales, chapter I, § 1. Spectres et caractères

For x∈Ax\in A to be invertible, it is necessary and sufficient that 0∉0\notin Sp(xx).

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

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Machine translation of the English, by gpt-5.4, gpt-5-6-mini, against glossary version 34. Not checked by a person. That model is a cut down version of the one the rest of this language was written by.