English
For x ∈ WithTop (OrderDual α) and y ∈ WithBot α, x ≤ y in the dual sense is equivalent to y ≤ x in the original sense.
Русский
Для x ∈ WithTop (OrderDual α) и y ∈ WithBot α, неравенство в двойственном порядке эквивалентно неравенству в исходном порядке.
LaTeX
$$$ x^{\mathrm{toDual}} \le y \iff y \le x. $$$$
Lean4
theorem ofDual_lt_iff {x : WithTop αᵒᵈ} {y : WithBot α} : WithTop.ofDual x < y ↔ WithBot.toDual y < x := by
cases x <;> cases y <;> simp [toDual_lt]