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Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Functions
funimaexg
Metamath Proof Explorer
Description: Axiom of Replacement using abbreviations. Axiom 39(vi) of Quine
p. 284. Compare Exercise 9 of TakeutiZaring p. 29. (Contributed by NM , 10-Sep-2006) Shorten proof and avoid ax-10 , ax-12 . (Revised by SN , 19-Dec-2024)
Ref
Expression
Assertion
funimaexg
⊢ Fun ⁡ A ∧ B ∈ C → A B ∈ V
Proof
Step
Hyp
Ref
Expression
1
dffun6
⊢ Fun ⁡ A ↔ Rel ⁡ A ∧ ∀ x ∃ * y x A y
2
1
simprbi
⊢ Fun ⁡ A → ∀ x ∃ * y x A y
3
dfima2
⊢ A B = y | ∃ x ∈ B x A y
4
axrep6g
⊢ B ∈ C ∧ ∀ x ∃ * y x A y → y | ∃ x ∈ B x A y ∈ V
5
3 4
eqeltrid
⊢ B ∈ C ∧ ∀ x ∃ * y x A y → A B ∈ V
6
2 5
sylan2
⊢ B ∈ C ∧ Fun ⁡ A → A B ∈ V
7
6
ancoms
⊢ Fun ⁡ A ∧ B ∈ C → A B ∈ V