Theorem crctcshlem1

Description: Lemma for crctcsh . (Contributed by AV, 10-Mar-2021)

	Ref	Expression
Hypotheses	crctcsh.v	⊢ 𝑉 = ( Vtx ‘ 𝐺 )
	crctcsh.i	⊢ 𝐼 = ( iEdg ‘ 𝐺 )
	crctcsh.d	⊢ ( 𝜑 → 𝐹 ( Circuits ‘ 𝐺 ) 𝑃 )
	crctcsh.n	⊢ 𝑁 = ( ♯ ‘ 𝐹 )
Assertion	crctcshlem1	⊢ ( 𝜑 → 𝑁 ∈ ℕ0 )

Proof

Step	Hyp	Ref	Expression
1		crctcsh.v	⊢ 𝑉 = ( Vtx ‘ 𝐺 )
2		crctcsh.i	⊢ 𝐼 = ( iEdg ‘ 𝐺 )
3		crctcsh.d	⊢ ( 𝜑 → 𝐹 ( Circuits ‘ 𝐺 ) 𝑃 )
4		crctcsh.n	⊢ 𝑁 = ( ♯ ‘ 𝐹 )
5		crctiswlk	⊢ ( 𝐹 ( Circuits ‘ 𝐺 ) 𝑃 → 𝐹 ( Walks ‘ 𝐺 ) 𝑃 )
6		wlkcl	⊢ ( 𝐹 ( Walks ‘ 𝐺 ) 𝑃 → ( ♯ ‘ 𝐹 ) ∈ ℕ0 )
7	4 6	eqeltrid	⊢ ( 𝐹 ( Walks ‘ 𝐺 ) 𝑃 → 𝑁 ∈ ℕ0 )
8	3 5 7	3syl	⊢ ( 𝜑 → 𝑁 ∈ ℕ0 )