Database
ZFC (ZERMELO-FRAENKEL WITH CHOICE) SET THEORY
ZFC Set Theory - add the Axiom of Choice
Introduce the Axiom of Choice
ac6sg
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ac6sf
Metamath Proof Explorer
Ascii
Unicode
Theorem
ac6sg
Description:
ac6s
with sethood as antecedent.
(Contributed by
FL
, 3-Aug-2009)
Ref
Expression
Hypothesis
ac6sg.1
⊢
y
=
f
⁡
x
→
φ
↔
ψ
Assertion
ac6sg
⊢
A
∈
V
→
∀
x
∈
A
∃
y
∈
B
φ
→
∃
f
f
:
A
⟶
B
∧
∀
x
∈
A
ψ
Proof
Step
Hyp
Ref
Expression
1
ac6sg.1
⊢
y
=
f
⁡
x
→
φ
↔
ψ
2
raleq
⊢
z
=
A
→
∀
x
∈
z
∃
y
∈
B
φ
↔
∀
x
∈
A
∃
y
∈
B
φ
3
feq2
⊢
z
=
A
→
f
:
z
⟶
B
↔
f
:
A
⟶
B
4
raleq
⊢
z
=
A
→
∀
x
∈
z
ψ
↔
∀
x
∈
A
ψ
5
3
4
anbi12d
⊢
z
=
A
→
f
:
z
⟶
B
∧
∀
x
∈
z
ψ
↔
f
:
A
⟶
B
∧
∀
x
∈
A
ψ
6
5
exbidv
⊢
z
=
A
→
∃
f
f
:
z
⟶
B
∧
∀
x
∈
z
ψ
↔
∃
f
f
:
A
⟶
B
∧
∀
x
∈
A
ψ
7
2
6
imbi12d
⊢
z
=
A
→
∀
x
∈
z
∃
y
∈
B
φ
→
∃
f
f
:
z
⟶
B
∧
∀
x
∈
z
ψ
↔
∀
x
∈
A
∃
y
∈
B
φ
→
∃
f
f
:
A
⟶
B
∧
∀
x
∈
A
ψ
8
vex
⊢
z
∈
V
9
8
1
ac6s
⊢
∀
x
∈
z
∃
y
∈
B
φ
→
∃
f
f
:
z
⟶
B
∧
∀
x
∈
z
ψ
10
7
9
vtoclg
⊢
A
∈
V
→
∀
x
∈
A
∃
y
∈
B
φ
→
∃
f
f
:
A
⟶
B
∧
∀
x
∈
A
ψ