English
For any f: αᵒᵈ → βᵒᵈ and a ∈ WithTop α, map f on the dual side equals map of a composed with dual.
Русский
Для f: αᵒᵈ → βᵒᵈ и a ∈ WithTop α: WithBot.map f (WithTop.toDual a) = a.map (toDual ∘ f).
LaTeX
$$$\\mathrm{WithBot}.map f (\\mathrm{WithTop}.toDual a) = a.map (toDual \\circ f)$$$
Lean4
theorem map_toDual (f : αᵒᵈ → βᵒᵈ) (a : WithTop α) : WithBot.map f (WithTop.toDual a) = a.map (toDual ∘ f) :=
rfl