Let x0 of type ι be given.
Let x1 of type ι be given.
Assume H2: x1 ∈ x0.
Let x2 of type ι be given.
Assume H3: x2 ∈ x0.
Apply unknownprop_d9ae82204b18e6cf15c85d865639887282bf3ebbe7f609859927820b6a09adb1 with
x0,
x1,
λ x3 . x2 leaving 4 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying H1.
The subproof is completed by applying H2.
Let x3 of type ι be given.
Assume H4: x3 ∈ x1.
The subproof is completed by applying H3.