Set U to be the term
X ∖ {y}.
We prove the intermediate
claim HyCl:
closed_in X Tx {y}.
We prove the intermediate
claim HUopen:
U ∈ Tx.
We prove the intermediate
claim HUin:
open_in X Tx U.
An
exact proof term for the current goal is
(open_in_elem X Tx U HUin).
We prove the intermediate
claim HxU:
x ∈ U.
An exact proof term for the current goal is HxX.
We prove the intermediate
claim Hxy:
x = y.
An
exact proof term for the current goal is
(SingE y x HxY).
An exact proof term for the current goal is (Hxyne Hxy).
Apply Hexh to the current goal.
Let h be given.
We prove the intermediate
claim Hhzero:
∀z : set, z ∈ X ∖ U → apply_fun h z = 0.
We prove the intermediate
claim Hhx1:
apply_fun h x = 1.
We prove the intermediate
claim HhJ:
h ∈ J.
Apply FalseE to the current goal.
We prove the intermediate
claim HyNotU:
y ∉ U.
We prove the intermediate
claim HyNotSing:
y ∉ {y}.
An
exact proof term for the current goal is
(setminusE2 X {y} y HyU).
An
exact proof term for the current goal is
(HyNotSing (SingI y)).
We prove the intermediate
claim HyOut:
y ∈ X ∖ U.
An
exact proof term for the current goal is
(setminusI X U y HyX HyNotU).
We prove the intermediate
claim Hhy0:
apply_fun h y = 0.
An exact proof term for the current goal is (Hhzero y HyOut).
rewrite the current goal using Heq (from left to right).
Use reflexivity.
We prove the intermediate
claim HFdef:
F = graph J (λf0 : set ⇒ f0).
rewrite the current goal using HFdef (from left to right).
rewrite the current goal using
(apply_fun_graph J (λf0 : set ⇒ f0) h HhJ) (from left to right).
Use reflexivity.
We prove the intermediate
claim HFdef:
F = graph J (λf0 : set ⇒ f0).
rewrite the current goal using HFdef (from left to right).
rewrite the current goal using
(apply_fun_graph J (λf0 : set ⇒ f0) h HhJ) (from left to right).
Use reflexivity.
rewrite the current goal using HcoordEqx (from right to left).
rewrite the current goal using HcoordEqy (from right to left).
An exact proof term for the current goal is HcoordEq.
We prove the intermediate
claim H10:
1 = 0.
rewrite the current goal using Hhx1 (from right to left) at position 1.
rewrite the current goal using Hhy0 (from right to left).
An exact proof term for the current goal is HhEq.
We prove the intermediate
claim Hpos01:
Rlt 0 1.
We prove the intermediate
claim Hbad:
Rlt 0 0.
rewrite the current goal using H10 (from right to left) at position 2.
An exact proof term for the current goal is Hpos01.