ScalingStacks

Lemma 1.16 . [0263]

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Lemma 1.16.

Let β€–.β€–\|\raisebox{1.72218pt}{.}\| be a norm of VV and 𝒱:=(V,β€–.β€–)≀1\mathscr{V}:=(V,\|\raisebox{1.72218pt}{.}\|)_{\leq 1}. Then

β€–v‖𝒱=inf{|b|∣b∈kΓ—Β andΒ β€–v‖≀|b|}.\|v\|_{\mathscr{V}}=\inf\{|b|\mid\text{$b\in k^{\times}$ and $\|v\|\leq|b|$}\}.

Moreover, β€–.‖≀‖.‖𝒱\|\raisebox{1.72218pt}{.}\|\leq\|\raisebox{1.72218pt}{.}\|_{\mathscr{V}} and β€–.‖𝒱≀|Ξ±|​‖.β€–\|\raisebox{1.72218pt}{.}\|_{\mathscr{V}}\leq|\alpha|\|\raisebox{1.72218pt}{.}\| for all α∈kΓ—\alpha\in k^{\times} with |Ξ±|>1|\alpha|>1.

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