ScalingStacks

0P98

Properties 7.2.3.

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    ff is invertible if and only if it is a homeomorphism and f⁡(Zo)⊂Zo′f(Z_{o})\subset Z^{\prime}_{o}.

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    f⁡(Ze​x​c)⊂Ze​x​c′f(Z_{exc})\subset Z^{\prime}_{exc} and C⁡(f):CZ​(z)→CZ′​(f⁡(z))C(f):C_{Z}(z)\to C_{Z^{\prime}}(f(z)) is ι\iota-equivariant for all z∈Zz\in Z.

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    ff restricts to a homeomorphism from f−1​(Z′−Ze​x​c′)f^{-1}(Z^{\prime}-Z^{\prime}_{exc}) to the open subset f⁡(Z)∩(Z′−Ze​x​c′)=f⁡(Z−Ze​x​c)∩(Z′−Ze​x​c′)f(Z)\cap(Z^{\prime}-Z^{\prime}_{exc})=f(Z-Z_{exc})\cap(Z^{\prime}-Z^{\prime}_{exc}) of Z′Z^{\prime}, since Zf⊂f−1​(Ze​x​c′)Z_{f}\subset f^{-1}(Z^{\prime}_{exc}). In particular, the restriction of ff to ZuZ_{u} is a homeomorphism Zu→∼f⁡(Zu)Z_{u}\mathrel{\mathop{\kern 0.0pt\to}\limits^{\sim}}f(Z_{u}).

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    If Z′Z^{\prime} is non-singular, then ff is an open embedding.

Original mathematics by the credited authors. Source collection and HTML conversion remain in progress.

Andrew Manion, Raphael Rouquier

Original source: arXiv:2009.09627v2