English
For x ∈ WithTop αᵒᵈ and y ∈ WithBot α, x < toDual y is equivalent to y < ofDual x (duality swaps inequalities).
Русский
Для x ∈ WithTop αᵒᵈ и y ∈ WithBot α, неравенство x < toDual(y) эквивалентно y < ofDual(x).
LaTeX
$$$ x < y^{\mathrm{toDual}} \iff y < x^{\mathrm{ofDual}}. $$$$
Lean4
theorem lt_toDual_iff {x : WithTop αᵒᵈ} {y : WithBot α} : x < y.toDual ↔ y < WithTop.ofDual x := by
cases x <;> cases y <;> simp [lt_toDual]