∀ {G : Type u_3} {α : Type u_2} [inst : AddGroup G] [inst_1 : AddAction G α] {zero : Type u_1} [inst_2 : Unique zero]
  (x : G) (x_1 : zero ↪ α),
  Function.Embedding.oneEmbeddingEquiv.toFun (x +ᵥ x_1) = Function.Embedding.oneEmbeddingEquiv.toFun (x +ᵥ x_1)