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ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Relations
imaeq2d
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imaeq12d
Metamath Proof Explorer
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Theorem
imaeq2d
Description:
Equality theorem for image.
(Contributed by
FL
, 15-Dec-2006)
Ref
Expression
Hypothesis
imaeq1d.1
⊢
φ
→
A
=
B
Assertion
imaeq2d
⊢
φ
→
C
A
=
C
B
Proof
Step
Hyp
Ref
Expression
1
imaeq1d.1
⊢
φ
→
A
=
B
2
imaeq2
⊢
A
=
B
→
C
A
=
C
B
3
1
2
syl
⊢
φ
→
C
A
=
C
B