Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι be given.
Apply H1 with
equip (ordsucc x0) (binunion x1 (Sing x2)).
Let x3 of type ι → ι be given.
Apply bijE with
x0,
x1,
x3,
equip (ordsucc x0) (binunion x1 (Sing x2)) leaving 2 subgoals.
The subproof is completed by applying H2.
Assume H3: ∀ x4 . x4 ∈ x0 ⟶ x3 x4 ∈ x1.
Assume H4: ∀ x4 . x4 ∈ x0 ⟶ ∀ x5 . x5 ∈ x0 ⟶ x3 x4 = x3 x5 ⟶ x4 = x5.
Assume H5:
∀ x4 . x4 ∈ x1 ⟶ ∃ x5 . and (x5 ∈ x0) (x3 x5 = x4).
Let x4 of type ο be given.
Apply H6 with
λ x5 . If_i (x5 ∈ x0) (x3 x5) x2.
Apply bijI with
ordsucc x0,
binunion x1 (Sing x2),
λ x5 . If_i (x5 ∈ x0) (x3 x5) x2 leaving 3 subgoals.
Let x5 of type ι be given.
Apply ordsuccE with
x0,
x5,
(λ x6 . If_i (x6 ∈ x0) (x3 x6) x2) x5 ∈ binunion x1 (Sing x2) leaving 3 subgoals.
The subproof is completed by applying H7.
Assume H8: x5 ∈ x0.
Apply If_i_1 with
x5 ∈ x0,
x3 x5,
x2,
λ x6 x7 . x7 ∈ binunion x1 (Sing x2) leaving 2 subgoals.
The subproof is completed by applying H8.
Apply binunionI1 with
x1,
Sing x2,
x3 x5.
Apply H3 with
x5.
The subproof is completed by applying H8.
Assume H8: x5 = x0.
Apply H8 with
λ x6 x7 . nIn x7 x0.
The subproof is completed by applying In_irref with x0.
Apply If_i_0 with
x5 ∈ x0,
x3 x5,
x2,
λ x6 x7 . x7 ∈ binunion x1 (Sing x2) leaving 2 subgoals.
The subproof is completed by applying L9.
Apply binunionI2 with
x1,
Sing x2,
x2.
The subproof is completed by applying SingI with x2.
Let x5 of type ι be given.
Let x6 of type ι be given.
Apply ordsuccE with
x0,
x5,
If_i (x5 ∈ x0) (x3 x5) x2 = If_i (x6 ∈ x0) (x3 x6) x2 ⟶ x5 = x6 leaving 3 subgoals.
The subproof is completed by applying H7.
Assume H9: x5 ∈ x0.
Apply If_i_1 with
x5 ∈ x0,
x3 x5,
x2,
λ x7 x8 . x8 = If_i (x6 ∈ x0) (x3 x6) x2 ⟶ x5 = x6 leaving 2 subgoals.
The subproof is completed by applying H9.
Apply ordsuccE with
x0,
x6,
x3 x5 = If_i (x6 ∈ x0) (x3 x6) x2 ⟶ x5 = x6 leaving 3 subgoals.
The subproof is completed by applying H8.
Assume H10: x6 ∈ x0.
Apply If_i_1 with
x6 ∈ x0,
x3 x6,
x2,
λ x7 x8 . x3 x5 = x8 ⟶ x5 = x6 leaving 2 subgoals.
The subproof is completed by applying H10.
Apply H4 with
x5,
x6 leaving 2 subgoals.
The subproof is completed by applying H9.
The subproof is completed by applying H10.
Assume H10: x6 = x0.
Apply If_i_0 with
x6 ∈ x0,
x3 x6,
x2,
λ x7 x8 . x3 ... = ... ⟶ x5 = x6 leaving 2 subgoals.