theorem instCoeDepTypeDaughterOfIs._proof_1
theorem instCoeDepTypeDaughterOfIs._proof_1: ∀ (x : Type) [yvbc459t.Daughter.Is x], yvbc459t.Daughter.Is x
theorem instCoeDepTypeDaughterOfIs._proof_1
theorem instCoeDepTypeDaughterOfIs._proof_1: ∀ (x : Type) [yvbc459t.Daughter.Is x], yvbc459t.Daughter.Is x