theorem instCoeObjectMaterialEntity._proof_1
theorem instCoeObjectMaterialEntity._proof_1: ∀ (v : d4qbfhxh.Object), d4qbfhxh.MaterialEntity.Is (Subtype.val v)
theorem instCoeObjectMaterialEntity._proof_1
theorem instCoeObjectMaterialEntity._proof_1: ∀ (v : d4qbfhxh.Object), d4qbfhxh.MaterialEntity.Is (Subtype.val v)