Proof of Theorem symgval
| Step | Hyp | Ref
| Expression |
| 1 | | df-symgrp 10334 |
. . 3
⊢ SymGrp = {〈x, y〉∣y
= {〈〈f, g〉, h〉∣(f:x–1-1-onto→x ⋀
g:x–1-1-onto→x ⋀
h = (f
∘ g))}} |
| 2 | 1 | fveq1i 3716 |
. 2
⊢ (SymGrp ‘A) = ({〈x,
y〉∣y = {〈〈f, g〉,
h〉∣(f:x–1-1-onto→x ⋀
g:x–1-1-onto→x ⋀
h = (f
∘ g))}} ‘A) |
| 3 | | elsymgrn.1 |
. . 3
⊢ A
∈ V |
| 4 | | elsymgrn.2 |
. . . . . . 7
⊢ P =
{x∣x:A–1-1-onto→A} |
| 5 | | equid 1124 |
. . . . . . . . 9
⊢ x =
x |
| 6 | 5 | biantru 723 |
. . . . . . . 8
⊢ (x:A–1-1-onto→A ↔
(x:A–1-1-onto→A ⋀
x = x)) |
| 7 | 6 | abbii 1572 |
. . . . . . 7
⊢ {x∣x:A–1-1-onto→A} =
{x∣(x:A–1-1-onto→A ⋀
x = x)} |
| 8 | 4, 7 | eqtr 1492 |
. . . . . 6
⊢ P =
{x∣(x:A–1-1-onto→A ⋀
x = x)} |
| 9 | 8 | f1oabexg 3691 |
. . . . 5
⊢ ((A
∈ V ⋀ A ∈ V)
→ P ∈ V) |
| 10 | 3, 3, 9 | mp2an 696 |
. . . 4
⊢ P
∈ V |
| 11 | 3, 4 | symgoprab 10336 |
. . . 4
⊢ {〈〈f, g〉,
h〉∣(f:A–1-1-onto→A ⋀
g:A–1-1-onto→A ⋀
h = (f
∘ g))} = {〈〈f, g〉,
h〉∣((f ∈ P
⋀ g ∈ P) ⋀ h =
(f ∘ g))} |
| 12 | 10, 10, 11 | oprabex2 4012 |
. . 3
⊢ {〈〈f, g〉,
h〉∣(f:A–1-1-onto→A ⋀
g:A–1-1-onto→A ⋀
h = (f
∘ g))} ∈ V |
| 13 | | f1oeq2 3676 |
. . . . . 6
⊢ (x =
A → (f:x–1-1-onto→x ↔
f:A–1-1-onto→x)) |
| 14 | | f1oeq3 3677 |
. . . . . 6
⊢ (x =
A → (f:A–1-1-onto→x ↔
f:A–1-1-onto→A)) |
| 15 | 13, 14 | bitrd 527 |
. . . . 5
⊢ (x =
A → (f:x–1-1-onto→x ↔
f:A–1-1-onto→A)) |
| 16 | | f1oeq2 3676 |
. . . . . 6
⊢ (x =
A → (g:x–1-1-onto→x ↔
g:A–1-1-onto→x)) |
| 17 | | f1oeq3 3677 |
. . . . . 6
⊢ (x =
A → (g:A–1-1-onto→x ↔
g:A–1-1-onto→A)) |
| 18 | 16, 17 | bitrd 527 |
. . . . 5
⊢ (x =
A → (g:x–1-1-onto→x ↔
g:A–1-1-onto→A)) |
| 19 | 15, 18 | 3anbi12d 892 |
. . . 4
⊢ (x =
A → ((f:x–1-1-onto→x ⋀
g:x–1-1-onto→x ⋀
h = (f
∘ g)) ↔ (f:A–1-1-onto→A ⋀
g:A–1-1-onto→A ⋀
h = (f
∘ g)))) |
| 20 | 19 | oprabbidv 3987 |
. . 3
⊢ (x =
A → {〈〈f, g〉,
h〉∣(f:x–1-1-onto→x ⋀
g:x–1-1-onto→x ⋀
h = (f
∘ g))} = {〈〈f, g〉,
h〉∣(f:A–1-1-onto→A ⋀
g:A–1-1-onto→A ⋀
h = (f
∘ g))}) |
| 21 | 3, 12, 20 | fvopab 3781 |
. 2
⊢ ({〈x, y〉∣y
= {〈〈f, g〉, h〉∣(f:x–1-1-onto→x ⋀
g:x–1-1-onto→x ⋀
h = (f
∘ g))}} ‘A) = {〈〈f, g〉,
h〉∣(f:A–1-1-onto→A ⋀
g:A–1-1-onto→A ⋀
h = (f
∘ g))} |
| 22 | 2, 21, 11 | 3eqtr 1496 |
1
⊢ (SymGrp ‘A) = {〈〈f, g〉,
h〉∣((f ∈ P
⋀ g ∈ P) ⋀ h =
(f ∘ g))} |