Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι be given.
Apply unknownprop_3647185bee823f297472e9b1979bff6804bdede7c0824747eee03864f4f342a6 with
λ x3 x4 : ι → ι → ι → ο . x4 x0 x1 x2 ⟶ x4 x0 x2 x1.
The subproof is completed by applying unknownprop_411872d9e62a7c55d0c5668a8fef0b88345bdb1b66aba80c7c02082fd86432f5 with
x0,
λ x3 . In x3 x1,
λ x3 . In x3 x2.