Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Union
Relations and functions (cont.)
fvclex
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fvresex
Metamath Proof Explorer
Ascii
Unicode
Theorem
fvclex
Description:
Existence of the class of values of a set.
(Contributed by
NM
, 9-Nov-1995)
Ref
Expression
Hypothesis
fvclex.1
⊢
F
∈
V
Assertion
fvclex
⊢
y
|
∃
x
y
=
F
⁡
x
∈
V
Proof
Step
Hyp
Ref
Expression
1
fvclex.1
⊢
F
∈
V
2
1
rnex
⊢
ran
⁡
F
∈
V
3
snex
⊢
∅
∈
V
4
2
3
unex
⊢
ran
⁡
F
∪
∅
∈
V
5
fvclss
⊢
y
|
∃
x
y
=
F
⁡
x
⊆
ran
⁡
F
∪
∅
6
4
5
ssexi
⊢
y
|
∃
x
y
=
F
⁡
x
∈
V