Proofgold Proof

pf
Let x0 of type ι be given. Apply Power_0_Sing_0 with λ x1 x2 . x0 ∈ x2 ⟶ x0 = 0. Assume H0: x0 ∈ Sing 0. Apply SingE with 0, x0. The subproof is completed by applying H0. ■