Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Relations
resex
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resindm
Metamath Proof Explorer
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Theorem
resex
Description:
The restriction of a set is a set.
(Contributed by
Jeff Madsen
, 19-Jun-2011)
Ref
Expression
Hypothesis
resex.1
⊢
A
∈
V
Assertion
resex
⊢
A
↾
B
∈
V
Proof
Step
Hyp
Ref
Expression
1
resex.1
⊢
A
∈
V
2
resexg
⊢
A
∈
V
→
A
↾
B
∈
V
3
1
2
ax-mp
⊢
A
↾
B
∈
V