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