Database
SURREAL NUMBERS
Sign sequence representation and Alling's axioms
Full-Eta Property
noinfcbv
Next ⟩
noinfno
Metamath Proof Explorer
Ascii
Unicode
Theorem
noinfcbv
Description:
Change bound variables for surreal infimum.
(Contributed by
Scott Fenton
, 9-Aug-2024)
Ref
Expression
Hypothesis
noinfcbv.1
ι
ι
ι
⊢
T
=
if
∃
x
∈
B
∀
y
∈
B
¬
y
<
s
x
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
∪
dom
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
1
𝑜
g
∈
y
|
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
⟼
ι
x
|
∃
u
∈
B
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
Assertion
noinfcbv
ι
ι
ι
⊢
T
=
if
∃
a
∈
B
∀
b
∈
B
¬
b
<
s
a
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
∪
dom
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
1
𝑜
c
∈
b
|
∃
d
∈
B
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
⟼
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
Proof
Step
Hyp
Ref
Expression
1
noinfcbv.1
ι
ι
ι
⊢
T
=
if
∃
x
∈
B
∀
y
∈
B
¬
y
<
s
x
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
∪
dom
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
1
𝑜
g
∈
y
|
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
⟼
ι
x
|
∃
u
∈
B
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
2
breq2
⊢
x
=
a
→
y
<
s
x
↔
y
<
s
a
3
2
notbid
⊢
x
=
a
→
¬
y
<
s
x
↔
¬
y
<
s
a
4
3
ralbidv
⊢
x
=
a
→
∀
y
∈
B
¬
y
<
s
x
↔
∀
y
∈
B
¬
y
<
s
a
5
breq1
⊢
y
=
b
→
y
<
s
a
↔
b
<
s
a
6
5
notbid
⊢
y
=
b
→
¬
y
<
s
a
↔
¬
b
<
s
a
7
6
cbvralvw
⊢
∀
y
∈
B
¬
y
<
s
a
↔
∀
b
∈
B
¬
b
<
s
a
8
4
7
bitrdi
⊢
x
=
a
→
∀
y
∈
B
¬
y
<
s
x
↔
∀
b
∈
B
¬
b
<
s
a
9
8
cbvrexvw
⊢
∃
x
∈
B
∀
y
∈
B
¬
y
<
s
x
↔
∃
a
∈
B
∀
b
∈
B
¬
b
<
s
a
10
8
cbvriotavw
ι
ι
⊢
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
=
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
11
10
dmeqi
ι
ι
⊢
dom
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
=
dom
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
12
11
opeq1i
ι
ι
⊢
dom
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
1
𝑜
=
dom
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
1
𝑜
13
12
sneqi
ι
ι
⊢
dom
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
1
𝑜
=
dom
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
1
𝑜
14
10
13
uneq12i
ι
ι
ι
ι
⊢
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
∪
dom
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
1
𝑜
=
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
∪
dom
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
1
𝑜
15
eleq1w
⊢
g
=
c
→
g
∈
dom
u
↔
c
∈
dom
u
16
suceq
⊢
g
=
c
→
suc
g
=
suc
c
17
16
reseq2d
⊢
g
=
c
→
u
↾
suc
g
=
u
↾
suc
c
18
16
reseq2d
⊢
g
=
c
→
v
↾
suc
g
=
v
↾
suc
c
19
17
18
eqeq12d
⊢
g
=
c
→
u
↾
suc
g
=
v
↾
suc
g
↔
u
↾
suc
c
=
v
↾
suc
c
20
19
imbi2d
⊢
g
=
c
→
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
↔
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
21
20
ralbidv
⊢
g
=
c
→
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
↔
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
22
fveqeq2
⊢
g
=
c
→
u
g
=
x
↔
u
c
=
x
23
15
21
22
3anbi123d
⊢
g
=
c
→
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
↔
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
x
24
23
rexbidv
⊢
g
=
c
→
∃
u
∈
B
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
↔
∃
u
∈
B
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
x
25
24
iotabidv
ι
ι
⊢
g
=
c
→
ι
x
|
∃
u
∈
B
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
=
ι
x
|
∃
u
∈
B
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
x
26
eqeq2
⊢
x
=
a
→
u
c
=
x
↔
u
c
=
a
27
26
3anbi3d
⊢
x
=
a
→
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
x
↔
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
a
28
27
rexbidv
⊢
x
=
a
→
∃
u
∈
B
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
x
↔
∃
u
∈
B
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
a
29
dmeq
⊢
u
=
d
→
dom
u
=
dom
d
30
29
eleq2d
⊢
u
=
d
→
c
∈
dom
u
↔
c
∈
dom
d
31
breq1
⊢
u
=
d
→
u
<
s
v
↔
d
<
s
v
32
31
notbid
⊢
u
=
d
→
¬
u
<
s
v
↔
¬
d
<
s
v
33
reseq1
⊢
u
=
d
→
u
↾
suc
c
=
d
↾
suc
c
34
33
eqeq1d
⊢
u
=
d
→
u
↾
suc
c
=
v
↾
suc
c
↔
d
↾
suc
c
=
v
↾
suc
c
35
32
34
imbi12d
⊢
u
=
d
→
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
↔
¬
d
<
s
v
→
d
↾
suc
c
=
v
↾
suc
c
36
35
ralbidv
⊢
u
=
d
→
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
↔
∀
v
∈
B
¬
d
<
s
v
→
d
↾
suc
c
=
v
↾
suc
c
37
breq2
⊢
v
=
e
→
d
<
s
v
↔
d
<
s
e
38
37
notbid
⊢
v
=
e
→
¬
d
<
s
v
↔
¬
d
<
s
e
39
reseq1
⊢
v
=
e
→
v
↾
suc
c
=
e
↾
suc
c
40
39
eqeq2d
⊢
v
=
e
→
d
↾
suc
c
=
v
↾
suc
c
↔
d
↾
suc
c
=
e
↾
suc
c
41
38
40
imbi12d
⊢
v
=
e
→
¬
d
<
s
v
→
d
↾
suc
c
=
v
↾
suc
c
↔
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
42
41
cbvralvw
⊢
∀
v
∈
B
¬
d
<
s
v
→
d
↾
suc
c
=
v
↾
suc
c
↔
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
43
36
42
bitrdi
⊢
u
=
d
→
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
↔
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
44
fveq1
⊢
u
=
d
→
u
c
=
d
c
45
44
eqeq1d
⊢
u
=
d
→
u
c
=
a
↔
d
c
=
a
46
30
43
45
3anbi123d
⊢
u
=
d
→
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
a
↔
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
47
46
cbvrexvw
⊢
∃
u
∈
B
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
a
↔
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
48
28
47
bitrdi
⊢
x
=
a
→
∃
u
∈
B
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
x
↔
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
49
48
cbviotavw
ι
ι
⊢
ι
x
|
∃
u
∈
B
c
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
c
=
v
↾
suc
c
∧
u
c
=
x
=
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
50
25
49
eqtrdi
ι
ι
⊢
g
=
c
→
ι
x
|
∃
u
∈
B
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
=
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
51
50
cbvmptv
ι
ι
⊢
g
∈
y
|
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
⟼
ι
x
|
∃
u
∈
B
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
=
c
∈
y
|
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
⟼
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
52
eleq1w
⊢
y
=
b
→
y
∈
dom
u
↔
b
∈
dom
u
53
suceq
⊢
y
=
b
→
suc
y
=
suc
b
54
53
reseq2d
⊢
y
=
b
→
u
↾
suc
y
=
u
↾
suc
b
55
53
reseq2d
⊢
y
=
b
→
v
↾
suc
y
=
v
↾
suc
b
56
54
55
eqeq12d
⊢
y
=
b
→
u
↾
suc
y
=
v
↾
suc
y
↔
u
↾
suc
b
=
v
↾
suc
b
57
56
imbi2d
⊢
y
=
b
→
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
↔
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
58
57
ralbidv
⊢
y
=
b
→
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
↔
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
59
52
58
anbi12d
⊢
y
=
b
→
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
↔
b
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
60
59
rexbidv
⊢
y
=
b
→
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
↔
∃
u
∈
B
b
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
61
29
eleq2d
⊢
u
=
d
→
b
∈
dom
u
↔
b
∈
dom
d
62
reseq1
⊢
u
=
d
→
u
↾
suc
b
=
d
↾
suc
b
63
62
eqeq1d
⊢
u
=
d
→
u
↾
suc
b
=
v
↾
suc
b
↔
d
↾
suc
b
=
v
↾
suc
b
64
32
63
imbi12d
⊢
u
=
d
→
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
↔
¬
d
<
s
v
→
d
↾
suc
b
=
v
↾
suc
b
65
64
ralbidv
⊢
u
=
d
→
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
↔
∀
v
∈
B
¬
d
<
s
v
→
d
↾
suc
b
=
v
↾
suc
b
66
reseq1
⊢
v
=
e
→
v
↾
suc
b
=
e
↾
suc
b
67
66
eqeq2d
⊢
v
=
e
→
d
↾
suc
b
=
v
↾
suc
b
↔
d
↾
suc
b
=
e
↾
suc
b
68
38
67
imbi12d
⊢
v
=
e
→
¬
d
<
s
v
→
d
↾
suc
b
=
v
↾
suc
b
↔
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
69
68
cbvralvw
⊢
∀
v
∈
B
¬
d
<
s
v
→
d
↾
suc
b
=
v
↾
suc
b
↔
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
70
65
69
bitrdi
⊢
u
=
d
→
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
↔
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
71
61
70
anbi12d
⊢
u
=
d
→
b
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
↔
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
72
71
cbvrexvw
⊢
∃
u
∈
B
b
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
b
=
v
↾
suc
b
↔
∃
d
∈
B
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
73
60
72
bitrdi
⊢
y
=
b
→
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
↔
∃
d
∈
B
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
74
73
cbvabv
⊢
y
|
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
=
b
|
∃
d
∈
B
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
75
74
mpteq1i
ι
ι
⊢
c
∈
y
|
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
⟼
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
=
c
∈
b
|
∃
d
∈
B
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
⟼
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
76
51
75
eqtri
ι
ι
⊢
g
∈
y
|
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
⟼
ι
x
|
∃
u
∈
B
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
=
c
∈
b
|
∃
d
∈
B
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
⟼
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
77
9
14
76
ifbieq12i
ι
ι
ι
ι
ι
ι
⊢
if
∃
x
∈
B
∀
y
∈
B
¬
y
<
s
x
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
∪
dom
ι
x
∈
B
|
∀
y
∈
B
¬
y
<
s
x
1
𝑜
g
∈
y
|
∃
u
∈
B
y
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
y
=
v
↾
suc
y
⟼
ι
x
|
∃
u
∈
B
g
∈
dom
u
∧
∀
v
∈
B
¬
u
<
s
v
→
u
↾
suc
g
=
v
↾
suc
g
∧
u
g
=
x
=
if
∃
a
∈
B
∀
b
∈
B
¬
b
<
s
a
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
∪
dom
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
1
𝑜
c
∈
b
|
∃
d
∈
B
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
⟼
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a
78
1
77
eqtri
ι
ι
ι
⊢
T
=
if
∃
a
∈
B
∀
b
∈
B
¬
b
<
s
a
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
∪
dom
ι
a
∈
B
|
∀
b
∈
B
¬
b
<
s
a
1
𝑜
c
∈
b
|
∃
d
∈
B
b
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
b
=
e
↾
suc
b
⟼
ι
a
|
∃
d
∈
B
c
∈
dom
d
∧
∀
e
∈
B
¬
d
<
s
e
→
d
↾
suc
c
=
e
↾
suc
c
∧
d
c
=
a