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00KA
Proposition 3.5 . There exist algebra norms ⦀ ⋅ ⦀ ϕ aff \vvvert\mathord{\cdot}\vvvert_{\phi}^{\mathrm{aff}} on V ∙ ( L ) V_{{\scriptscriptstyle\bullet}}(L) and ⦀ ⋅ ⦀ ϕ , X | Y aff \vvvert\mathord{\cdot}\vvvert_{\phi,X|Y}^{\mathrm{aff}} on V ∙ ( L X | Y ) V_{{\scriptscriptstyle\bullet}}(L_{X|Y}) such that the separated completions of
( V ∙ ( L ) , ⦀ ⋅ ⦀ ϕ aff ) (V_{{\scriptscriptstyle\bullet}}(L),\vvvert\mathord{\cdot}\vvvert_{\phi}^{\mathrm{aff}}) and ( V ∙ ( L X | Y ) , ⦀ ⋅ ⦀ ϕ , X | Y aff ) (V_{{\scriptscriptstyle\bullet}}(L_{X|Y}),\vvvert\mathord{\cdot}\vvvert_{\phi,X|Y}^{\mathrm{aff}}) are affinoid algebras. Denote them by V ^ ∙ ( L , ϕ aff ) \widehat{V}_{{\scriptscriptstyle\bullet}}(L,\phi^{\mathrm{aff}}) and V ^ ∙ ( L X | Y , ϕ X | Y aff ) \widehat{V}_{{\scriptscriptstyle\bullet}}(L_{X|Y},\phi_{X|Y}^{\mathrm{aff}}) . Moreover, there exists a commutative diagram of homomorphisms of k k -algebras with σ \sigma and σ Y \sigma_{Y} being homomorphisms of Banach k k -algebras
V ∙ ( L ) \textstyle{V_{{\scriptscriptstyle\bullet}}(L)\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces} i Y \scriptstyle{i_{Y}} V ^ ∙ ( L , ϕ aff ) \textstyle{\widehat{V}_{{\scriptscriptstyle\bullet}}(L,\phi^{\mathrm{aff}})\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces} σ \scriptstyle{\sigma} i Y ( ϕ aff ) \scriptstyle{i_{Y}(\phi^{\mathrm{aff}})} V ^ ∙ ( L , ϕ ) \textstyle{\widehat{V}_{{\scriptscriptstyle\bullet}}(L,\phi)\ignorespaces\ignorespaces\ignorespaces\ignorespaces} i Y ( ϕ ) \scriptstyle{i_{Y}(\phi)} V ∙ ( L X | Y ) \textstyle{V_{{\scriptscriptstyle\bullet}}(L_{X|Y})\ignorespaces\ignorespaces\ignorespaces\ignorespaces} V ^ ∙ ( L X | Y , ϕ X | Y aff ) \textstyle{\widehat{V}_{{\scriptscriptstyle\bullet}}(L_{X|Y},\phi_{X|Y}^{\mathrm{aff}})\ignorespaces\ignorespaces\ignorespaces\ignorespaces} σ | Y \scriptstyle{\sigma|_{Y}} V ^ ∙ ( L X | Y , ϕ X | Y ) \textstyle{\widehat{V}_{{\scriptscriptstyle\bullet}}(L_{X|Y},\phi_{X|Y})}
All homomorphisms (except i Y i_{Y} ) have dense images, and i Y i_{Y} is surjective.
00KB
Proof. As V ∙ ( L ) V_{{\scriptscriptstyle\bullet}}(L) is a finitely generated sub-k k -algebra of V ^ ∙ ( L , ϕ ) \widehat{V}_{{\scriptscriptstyle\bullet}}(L,\phi) which is dense for the topology induced by Banach algebra norm, by Proposition 2.44 , there exists an affinoid algebra norm ⦀ ⋅ ⦀ ϕ aff \vvvert\mathord{\cdot}\vvvert_{\phi}^{\mathrm{aff}} on V ∙ ( L ) V_{{\scriptscriptstyle\bullet}}(L) and a homomorphism of Banach algebras
σ : V ^ ∙ ( L , ϕ aff ) → V ^ ∙ ( L , ϕ ) . \sigma:\widehat{V}_{{\scriptscriptstyle\bullet}}(L,\phi^{\mathrm{aff}})\rightarrow\widehat{V}_{{\scriptscriptstyle\bullet}}(L,\phi).
One then takes ⦀ ⋅ ⦀ ϕ , X | Y aff \vvvert\mathord{\cdot}\vvvert_{\phi,X|Y}^{\mathrm{aff}} on V ∙ ( L X | Y ) V_{{\scriptscriptstyle\bullet}}(L_{X|Y}) to be the quotient norm of ⦀ ⋅ ⦀ ϕ aff \vvvert\mathord{\cdot}\vvvert_{\phi}^{\mathrm{aff}} . By Example 2.42 , this quotient norm is also an affinoid algebra norm. By this quotient construction, there exists a homomorphism of Banach k k -algebras
σ | Y : V ^ ∙ ( L X | Y , ϕ X | Y aff ) → V ^ ∙ ( L X | Y , ϕ X | Y ) \sigma|_{Y}:\widehat{V}_{{\scriptscriptstyle\bullet}}(L_{X|Y},\phi_{X|Y}^{\mathrm{aff}})\rightarrow\widehat{V}_{{\scriptscriptstyle\bullet}}(L_{X|Y},\phi_{X|Y})
which fits into a commutative diagram with i Y ( ϕ ) i_{Y}(\phi) and i Y ( ϕ aff ) i_{Y}(\phi^{\mathrm{aff}}) .
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