densely_ordered : Π (α : Type u_1) [_inst_1 : preorder α], Prop
densely_ordered.mk :
  ∀ {α : Type u_1} [_inst_1 : preorder α],
    (∀ (a c : α), a < c → (∃ (b : α), a < b ∧ b < c)) → densely_ordered α
densely_ordered.dense :
  ∀ {α : Type u_1} [_inst_1 : preorder α] [c : densely_ordered α] (a c : α),
    a < c → (∃ (b : α), a < b ∧ b < c)
