Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Functions in maps-to notation
mpteq2daOLD
Metamath Proof Explorer
Description: Obsolete version of mpteq2da as of 11-Nov-2024. (Contributed by FL , 14-Sep-2013) (Revised by Mario Carneiro , 16-Dec-2013)
(Proof modification is discouraged.) (New usage is discouraged.)
Ref
Expression
Hypotheses
mpteq2da.1
⊢ Ⅎ 𝑥 𝜑
mpteq2da.2
⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐴 ) → 𝐵 = 𝐶 )
Assertion
mpteq2daOLD
⊢ ( 𝜑 → ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) = ( 𝑥 ∈ 𝐴 ↦ 𝐶 ) )
Proof
Step
Hyp
Ref
Expression
1
mpteq2da.1
⊢ Ⅎ 𝑥 𝜑
2
mpteq2da.2
⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝐴 ) → 𝐵 = 𝐶 )
3
eqid
⊢ 𝐴 = 𝐴
4
3
ax-gen
⊢ ∀ 𝑥 𝐴 = 𝐴
5
2
ex
⊢ ( 𝜑 → ( 𝑥 ∈ 𝐴 → 𝐵 = 𝐶 ) )
6
1 5
ralrimi
⊢ ( 𝜑 → ∀ 𝑥 ∈ 𝐴 𝐵 = 𝐶 )
7
mpteq12f
⊢ ( ( ∀ 𝑥 𝐴 = 𝐴 ∧ ∀ 𝑥 ∈ 𝐴 𝐵 = 𝐶 ) → ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) = ( 𝑥 ∈ 𝐴 ↦ 𝐶 ) )
8
4 6 7
sylancr
⊢ ( 𝜑 → ( 𝑥 ∈ 𝐴 ↦ 𝐵 ) = ( 𝑥 ∈ 𝐴 ↦ 𝐶 ) )