ScalingStacks

Example 3.70 . [02ML]

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Example 3.70.

Consider the standard simplex Δn\Delta^{n} of Example 3.65. Its indicator function induces the standard polyhedral complex in Δn\Delta^{n} consisting of the collection of its faces. The dual of ιΔn\iota_{\Delta^{n}}, the support function ΨΔn\Psi_{\Delta^{n}}, induces a fan ΣΔn:=Π⁡(ΨΔn)\Sigma_{\Delta^{n}}:=\Pi(\Psi_{\Delta^{n}}) of NℝN_{\mathbb{R}}. The duality between these polyhedral complexes can be made explicit as

Π⁡(ιΔn)⟶ΣΔn,F⟼∠​(F,Δn)∨.\Pi(\iota_{\Delta^{n}})\longrightarrow\Sigma_{\Delta^{n}},\quad F\longmapsto\angle(F,\Delta^{n})^{\vee}.

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