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ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Functions
fveqeq2d
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fveqeq2
Metamath Proof Explorer
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Unicode
Theorem
fveqeq2d
Description:
Equality deduction for function value.
(Contributed by
BJ
, 30-Aug-2022)
Ref
Expression
Hypothesis
fveqeq2d.1
⊢
φ
→
A
=
B
Assertion
fveqeq2d
⊢
φ
→
F
⁡
A
=
C
↔
F
⁡
B
=
C
Proof
Step
Hyp
Ref
Expression
1
fveqeq2d.1
⊢
φ
→
A
=
B
2
1
fveq2d
⊢
φ
→
F
⁡
A
=
F
⁡
B
3
2
eqeq1d
⊢
φ
→
F
⁡
A
=
C
↔
F
⁡
B
=
C