Bourbaki

Corollary

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

Théories spectrales, chapter I, § 6. Algèbres stellaires

Let A be a commutative involutive Banach algebra and jj the canonical morphism of A into Stell(A). The mapping X(j)\mathsf{X}(j) is a homeomorphism of X\mathsf{X}(Stell(A)) onto the subspace X(A)h\mathsf{X}(A)_h of X(A)\mathsf{X}(A) formed by the Hermitian characters of A.

The Hermitian characters of A are the morphisms of involutive algebras from A into the stellar algebra C\mathbf{C}. Prop. 20 therefore entails that X(j)\mathsf{X}(j) is a bijection of X\mathsf{X}(Stell(A)) onto X(A)h\mathsf{X}(A)_h. Since X(j)\mathsf{X}(j) is a homeomorphism onto its image (cf. I, p. 10), the corollary follows.

We identify X\mathsf{X}(Stell(A)) with X(A)h\mathsf{X}(A)_h by means of the mapping X(j)\mathsf{X}(j). For every x∈x\in A, the mapping GStell(A)(j(x))\mathscr{G}_{Stell(A)}(j(x)) is none other than the restriction of GA(x)\mathscr{G}_A(x) to X(A)h\mathsf{X}(A)_h.

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.

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Machine translation of the English, by gpt-5-6-mini, gpt-5.4, 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.