Let x0 of type ι be given.
Let x1 of type ι be given.
Assume H1: x1 ∈ x0.
Apply ordinal_Hered with
x0,
x1 leaving 2 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying H1.
Apply ordinal_SNo with
x1.
The subproof is completed by applying L2.
Apply ordinal_SNoLev with
x1.
The subproof is completed by applying L2.
Apply ordinal_SNoLev_max with
x0,
x1 leaving 3 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying L3.
Apply L4 with
λ x2 x3 . x3 ∈ x0.
The subproof is completed by applying H1.