Description: Define the collection of simple paths of a fixed length as word over the set of vertices. (Contributed by Alexander van der Vekens, 1-Mar-2018) (Revised by AV, 11-May-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-wspthsn | |- WSPathsN = ( n e. NN0 , g e. _V |-> { w e. ( n WWalksN g ) | E. f f ( SPaths ` g ) w } ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 0 | cwwspthsn | |- WSPathsN | |
| 1 | vn | |- n | |
| 2 | cn0 | |- NN0 | |
| 3 | vg | |- g | |
| 4 | cvv | |- _V | |
| 5 | vw | |- w | |
| 6 | 1 | cv | |- n | 
| 7 | cwwlksn | |- WWalksN | |
| 8 | 3 | cv | |- g | 
| 9 | 6 8 7 | co | |- ( n WWalksN g ) | 
| 10 | vf | |- f | |
| 11 | 10 | cv | |- f | 
| 12 | cspths | |- SPaths | |
| 13 | 8 12 | cfv | |- ( SPaths ` g ) | 
| 14 | 5 | cv | |- w | 
| 15 | 11 14 13 | wbr | |- f ( SPaths ` g ) w | 
| 16 | 15 10 | wex | |- E. f f ( SPaths ` g ) w | 
| 17 | 16 5 9 | crab |  |-  { w e. ( n WWalksN g ) | E. f f ( SPaths ` g ) w } | 
| 18 | 1 3 2 4 17 | cmpo |  |-  ( n e. NN0 , g e. _V |-> { w e. ( n WWalksN g ) | E. f f ( SPaths ` g ) w } ) | 
| 19 | 0 18 | wceq |  |-  WSPathsN = ( n e. NN0 , g e. _V |-> { w e. ( n WWalksN g ) | E. f f ( SPaths ` g ) w } ) |