Let x0 of type ι → ι → ο be given.
Assume H0:
∀ x1 . ordinal x1 ⟶ ∀ x2 . ordinal x2 ⟶ ∀ x3 . x3 ∈ SNoS_ x1 ⟶ ∀ x4 . x4 ∈ SNoS_ x2 ⟶ x0 x3 x4.
Let x1 of type ι be given.
Let x2 of type ι be given.
Apply SNoLev_ordinal with
x1.
The subproof is completed by applying H1.
Apply ordinal_ordsucc with
SNoLev x1.
The subproof is completed by applying L3.
Apply SNoS_SNoLev with
x1.
The subproof is completed by applying H1.
Apply SNoLev_ordinal with
x2.
The subproof is completed by applying H2.
Apply ordinal_ordsucc with
SNoLev x2.
The subproof is completed by applying L6.
Apply SNoS_SNoLev with
x2.
The subproof is completed by applying H2.
Apply H0 with
ordsucc (SNoLev x1),
ordsucc (SNoLev x2),
x1,
x2 leaving 4 subgoals.
The subproof is completed by applying L4.
The subproof is completed by applying L7.
The subproof is completed by applying L5.
The subproof is completed by applying L8.