Let x0 of type ι be given.
Apply unknownprop_d680330ebcfadd4f64e543de2cb6fc42bf4aa9a615b1c36ce2648f1c3c509a67 with
λ x1 x2 : ι → ο . x2 x0.
Apply unknownprop_389e2fb1855352fcc964ea44fe6723d7a1c2d512f04685300e3e97621725b977 with
atleast2 x0,
not (atleast3 x0) leaving 2 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying H1.