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strfv2
Metamath Proof Explorer
Description: A variation on strfv to avoid asserting that S itself is a
function, which involves sethood of all the ordered pair components of
S . (Contributed by Mario Carneiro , 30-Apr-2015)
Ref
Expression
Hypotheses
strfv2.s
⊢ S ∈ V
strfv2.f
⊢ Fun ⁡ S -1 -1
strfv2.e
⊢ E = Slot E ⁡ ndx
strfv2.n
⊢ E ⁡ ndx C ∈ S
Assertion
strfv2
⊢ C ∈ V → C = E ⁡ S
Proof
Step
Hyp
Ref
Expression
1
strfv2.s
⊢ S ∈ V
2
strfv2.f
⊢ Fun ⁡ S -1 -1
3
strfv2.e
⊢ E = Slot E ⁡ ndx
4
strfv2.n
⊢ E ⁡ ndx C ∈ S
5
1
a1i
⊢ C ∈ V → S ∈ V
6
2
a1i
⊢ C ∈ V → Fun ⁡ S -1 -1
7
4
a1i
⊢ C ∈ V → E ⁡ ndx C ∈ S
8
id
⊢ C ∈ V → C ∈ V
9
3 5 6 7 8
strfv2d
⊢ C ∈ V → C = E ⁡ S