Step | Hyp | Ref | Expression |
1 |
|
axext |
upto (suc a) == a ; upto a -> upto (suc a) = a ; upto a |
2 |
|
bitr4 |
(x e. upto (suc a) <-> x < suc a) -> (x e. a ; upto a <-> x < suc a) -> (x e. upto (suc a) <-> x e. a ; upto a) |
3 |
|
elupto |
x e. upto (suc a) <-> x < suc a |
4 |
2, 3 |
ax_mp |
(x e. a ; upto a <-> x < suc a) -> (x e. upto (suc a) <-> x e. a ; upto a) |
5 |
|
bitr4 |
(x e. a ; upto a <-> x = a \/ x e. upto a) -> (x < suc a <-> x = a \/ x e. upto a) -> (x e. a ; upto a <-> x < suc a) |
6 |
|
elins |
x e. a ; upto a <-> x = a \/ x e. upto a |
7 |
5, 6 |
ax_mp |
(x < suc a <-> x = a \/ x e. upto a) -> (x e. a ; upto a <-> x < suc a) |
8 |
|
bitr3 |
(x <= a <-> x < suc a) -> (x <= a <-> x = a \/ x e. upto a) -> (x < suc a <-> x = a \/ x e. upto a) |
9 |
|
leltsuc |
x <= a <-> x < suc a |
10 |
8, 9 |
ax_mp |
(x <= a <-> x = a \/ x e. upto a) -> (x < suc a <-> x = a \/ x e. upto a) |
11 |
|
bitr4 |
(x <= a <-> x < a \/ x = a) -> (x = a \/ x e. upto a <-> x < a \/ x = a) -> (x <= a <-> x = a \/ x e. upto a) |
12 |
|
leloe |
x <= a <-> x < a \/ x = a |
13 |
11, 12 |
ax_mp |
(x = a \/ x e. upto a <-> x < a \/ x = a) -> (x <= a <-> x = a \/ x e. upto a) |
14 |
|
bitr |
(x = a \/ x e. upto a <-> x e. upto a \/ x = a) -> (x e. upto a \/ x = a <-> x < a \/ x = a) -> (x = a \/ x e. upto a <-> x < a \/ x = a) |
15 |
|
orcomb |
x = a \/ x e. upto a <-> x e. upto a \/ x = a |
16 |
14, 15 |
ax_mp |
(x e. upto a \/ x = a <-> x < a \/ x = a) -> (x = a \/ x e. upto a <-> x < a \/ x = a) |
17 |
|
oreq1 |
(x e. upto a <-> x < a) -> (x e. upto a \/ x = a <-> x < a \/ x = a) |
18 |
|
elupto |
x e. upto a <-> x < a |
19 |
17, 18 |
ax_mp |
x e. upto a \/ x = a <-> x < a \/ x = a |
20 |
16, 19 |
ax_mp |
x = a \/ x e. upto a <-> x < a \/ x = a |
21 |
13, 20 |
ax_mp |
x <= a <-> x = a \/ x e. upto a |
22 |
10, 21 |
ax_mp |
x < suc a <-> x = a \/ x e. upto a |
23 |
7, 22 |
ax_mp |
x e. a ; upto a <-> x < suc a |
24 |
4, 23 |
ax_mp |
x e. upto (suc a) <-> x e. a ; upto a |
25 |
24 |
ax_gen |
A. x (x e. upto (suc a) <-> x e. a ; upto a) |
26 |
25 |
conv eqs |
upto (suc a) == a ; upto a |
27 |
1, 26 |
ax_mp |
upto (suc a) = a ; upto a |