English
Let R be a relation R: α → β → Prop. If α is empty, then BiTotal R is equivalent to β being empty.
Русский
Пусть R — отношение α → β → Prop. Если α пусто, BiTotal(R) эквивалентно пустоте β.
LaTeX
$$$ [\operatorname{IsEmpty}(\alpha)] \Rightarrow \big( \operatorname{BiTotal}(R) \iff \operatorname{IsEmpty}(\beta) \big) $$$
Lean4
theorem biTotal_iff_isEmpty_right [IsEmpty α] : BiTotal R ↔ IsEmpty β := by
simp only [BiTotal, leftTotal_empty, rightTotal_iff_isEmpty_right, true_and]