diff --git a/src/order/bounded_order.lean b/src/order/bounded_order.lean index 7ee9080baa457..fb95dc648449d 100644 --- a/src/order/bounded_order.lean +++ b/src/order/bounded_order.lean @@ -1010,6 +1010,21 @@ lemma min_top_right [order_top α] (a : α) : min a ⊤ = a := min_eq_left le_to lemma max_bot_left [order_bot α] (a : α) : max (⊥ : α) a = a := max_eq_right bot_le lemma max_bot_right [order_bot α] (a : α) : max a ⊥ = a := max_eq_left bot_le +-- `simp` can prove these, so they shouldn't be simp-lemmas. +lemma min_bot_left [order_bot α] (a : α) : min ⊥ a = ⊥ := min_eq_left bot_le +lemma min_bot_right [order_bot α] (a : α) : min a ⊥ = ⊥ := min_eq_right bot_le +lemma max_top_left [order_top α] (a : α) : max ⊤ a = ⊤ := max_eq_left le_top +lemma max_top_right [order_top α] (a : α) : max a ⊤ = ⊤ := max_eq_right le_top + +@[simp] lemma min_eq_bot [order_bot α] {a b : α} : min a b = ⊥ ↔ a = ⊥ ∨ b = ⊥ := +by { symmetry, cases le_total a b; simpa [*, min_eq_left, min_eq_right] using eq_bot_mono h } + +@[simp] lemma max_eq_top [order_top α] {a b : α} : max a b = ⊤ ↔ a = ⊤ ∨ b = ⊤ := +@min_eq_bot (order_dual α) _ _ a b + +@[simp] lemma max_eq_bot [order_bot α] {a b : α} : max a b = ⊥ ↔ a = ⊥ ∧ b = ⊥ := sup_eq_bot_iff +@[simp] lemma min_eq_top [order_top α] {a b : α} : min a b = ⊤ ↔ a = ⊤ ∧ b = ⊤ := inf_eq_top_iff + end linear_order section distrib_lattice_bot