Apply unknownprop_abe15cc9bd131c95b0b9585b43caa22ca6fcee57a092fd0cd1b55cd95e75595e with
λ x0 x1 : ι → ι → ι . ∀ x2 . ∀ x3 : ι → ι . ∀ x4 : ι → ι → ι . ∀ x5 . In x5 (lam2 x2 x3 x4) ⟶ ∃ x6 . and (In x6 x2) (∃ x7 . and (In x7 (x3 x6)) (∃ x8 . and (In x8 (x4 x6 x7)) (x5 = x0 x6 (x0 x7 x8)))).
The subproof is completed by applying unknownprop_dd3c297cc9f428510d46ad676c83d33847a3486f14c109211c1e883e61993257.