Metamath Proof Explorer


Definition df-wwlksnon

Description: Define the collection of walks of a fixed length with particular endpoints as word over the set of vertices. (Contributed by Alexander van der Vekens, 15-Feb-2018) (Revised by AV, 11-May-2021)

Ref Expression
Assertion df-wwlksnon WWalksNOn = ( 𝑛 ∈ ℕ0 , 𝑔 ∈ V ↦ ( 𝑎 ∈ ( Vtx ‘ 𝑔 ) , 𝑏 ∈ ( Vtx ‘ 𝑔 ) ↦ { 𝑤 ∈ ( 𝑛 WWalksN 𝑔 ) ∣ ( ( 𝑤 ‘ 0 ) = 𝑎 ∧ ( 𝑤𝑛 ) = 𝑏 ) } ) )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cwwlksnon WWalksNOn
1 vn 𝑛
2 cn0 0
3 vg 𝑔
4 cvv V
5 va 𝑎
6 cvtx Vtx
7 3 cv 𝑔
8 7 6 cfv ( Vtx ‘ 𝑔 )
9 vb 𝑏
10 vw 𝑤
11 1 cv 𝑛
12 cwwlksn WWalksN
13 11 7 12 co ( 𝑛 WWalksN 𝑔 )
14 10 cv 𝑤
15 cc0 0
16 15 14 cfv ( 𝑤 ‘ 0 )
17 5 cv 𝑎
18 16 17 wceq ( 𝑤 ‘ 0 ) = 𝑎
19 11 14 cfv ( 𝑤𝑛 )
20 9 cv 𝑏
21 19 20 wceq ( 𝑤𝑛 ) = 𝑏
22 18 21 wa ( ( 𝑤 ‘ 0 ) = 𝑎 ∧ ( 𝑤𝑛 ) = 𝑏 )
23 22 10 13 crab { 𝑤 ∈ ( 𝑛 WWalksN 𝑔 ) ∣ ( ( 𝑤 ‘ 0 ) = 𝑎 ∧ ( 𝑤𝑛 ) = 𝑏 ) }
24 5 9 8 8 23 cmpo ( 𝑎 ∈ ( Vtx ‘ 𝑔 ) , 𝑏 ∈ ( Vtx ‘ 𝑔 ) ↦ { 𝑤 ∈ ( 𝑛 WWalksN 𝑔 ) ∣ ( ( 𝑤 ‘ 0 ) = 𝑎 ∧ ( 𝑤𝑛 ) = 𝑏 ) } )
25 1 3 2 4 24 cmpo ( 𝑛 ∈ ℕ0 , 𝑔 ∈ V ↦ ( 𝑎 ∈ ( Vtx ‘ 𝑔 ) , 𝑏 ∈ ( Vtx ‘ 𝑔 ) ↦ { 𝑤 ∈ ( 𝑛 WWalksN 𝑔 ) ∣ ( ( 𝑤 ‘ 0 ) = 𝑎 ∧ ( 𝑤𝑛 ) = 𝑏 ) } ) )
26 0 25 wceq WWalksNOn = ( 𝑛 ∈ ℕ0 , 𝑔 ∈ V ↦ ( 𝑎 ∈ ( Vtx ‘ 𝑔 ) , 𝑏 ∈ ( Vtx ‘ 𝑔 ) ↦ { 𝑤 ∈ ( 𝑛 WWalksN 𝑔 ) ∣ ( ( 𝑤 ‘ 0 ) = 𝑎 ∧ ( 𝑤𝑛 ) = 𝑏 ) } ) )