Metamath Proof Explorer


Theorem eulerpartlemelr

Description: Lemma for eulerpart . (Contributed by Thierry Arnoux, 8-Aug-2018)

Ref Expression
Hypotheses eulerpartlems.r 𝑅 = { 𝑓 ∣ ( 𝑓 “ ℕ ) ∈ Fin }
eulerpartlems.s 𝑆 = ( 𝑓 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) ↦ Σ 𝑘 ∈ ℕ ( ( 𝑓𝑘 ) · 𝑘 ) )
Assertion eulerpartlemelr ( 𝐴 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) → ( 𝐴 : ℕ ⟶ ℕ0 ∧ ( 𝐴 “ ℕ ) ∈ Fin ) )

Proof

Step Hyp Ref Expression
1 eulerpartlems.r 𝑅 = { 𝑓 ∣ ( 𝑓 “ ℕ ) ∈ Fin }
2 eulerpartlems.s 𝑆 = ( 𝑓 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) ↦ Σ 𝑘 ∈ ℕ ( ( 𝑓𝑘 ) · 𝑘 ) )
3 inss1 ( ( ℕ0m ℕ ) ∩ 𝑅 ) ⊆ ( ℕ0m ℕ )
4 3 sseli ( 𝐴 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) → 𝐴 ∈ ( ℕ0m ℕ ) )
5 elmapi ( 𝐴 ∈ ( ℕ0m ℕ ) → 𝐴 : ℕ ⟶ ℕ0 )
6 4 5 syl ( 𝐴 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) → 𝐴 : ℕ ⟶ ℕ0 )
7 inss2 ( ( ℕ0m ℕ ) ∩ 𝑅 ) ⊆ 𝑅
8 7 sseli ( 𝐴 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) → 𝐴𝑅 )
9 cnveq ( 𝑓 = 𝐴 𝑓 = 𝐴 )
10 9 imaeq1d ( 𝑓 = 𝐴 → ( 𝑓 “ ℕ ) = ( 𝐴 “ ℕ ) )
11 10 eleq1d ( 𝑓 = 𝐴 → ( ( 𝑓 “ ℕ ) ∈ Fin ↔ ( 𝐴 “ ℕ ) ∈ Fin ) )
12 11 1 elab2g ( 𝐴 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) → ( 𝐴𝑅 ↔ ( 𝐴 “ ℕ ) ∈ Fin ) )
13 8 12 mpbid ( 𝐴 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) → ( 𝐴 “ ℕ ) ∈ Fin )
14 6 13 jca ( 𝐴 ∈ ( ( ℕ0m ℕ ) ∩ 𝑅 ) → ( 𝐴 : ℕ ⟶ ℕ0 ∧ ( 𝐴 “ ℕ ) ∈ Fin ) )