Metamath Proof Explorer


Theorem wwlkbp

Description: Basic properties of a walk (in an undirected graph) as word. (Contributed by Alexander van der Vekens, 15-Jul-2018) (Revised by AV, 9-Apr-2021)

Ref Expression
Hypothesis wwlkbp.v 𝑉 = ( Vtx ‘ 𝐺 )
Assertion wwlkbp ( 𝑊 ∈ ( WWalks ‘ 𝐺 ) → ( 𝐺 ∈ V ∧ 𝑊 ∈ Word 𝑉 ) )

Proof

Step Hyp Ref Expression
1 wwlkbp.v 𝑉 = ( Vtx ‘ 𝐺 )
2 elfvex ( 𝑊 ∈ ( WWalks ‘ 𝐺 ) → 𝐺 ∈ V )
3 eqid ( Edg ‘ 𝐺 ) = ( Edg ‘ 𝐺 )
4 1 3 iswwlks ( 𝑊 ∈ ( WWalks ‘ 𝐺 ) ↔ ( 𝑊 ≠ ∅ ∧ 𝑊 ∈ Word 𝑉 ∧ ∀ 𝑖 ∈ ( 0 ..^ ( ( ♯ ‘ 𝑊 ) − 1 ) ) { ( 𝑊𝑖 ) , ( 𝑊 ‘ ( 𝑖 + 1 ) ) } ∈ ( Edg ‘ 𝐺 ) ) )
5 4 simp2bi ( 𝑊 ∈ ( WWalks ‘ 𝐺 ) → 𝑊 ∈ Word 𝑉 )
6 2 5 jca ( 𝑊 ∈ ( WWalks ‘ 𝐺 ) → ( 𝐺 ∈ V ∧ 𝑊 ∈ Word 𝑉 ) )