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Description: The set of trails (in an undirected graph). (Contributed by Alexander van der Vekens, 20-Oct-2017) (Revised by AV, 28-Dec-2020) (Revised by AV, 29-Oct-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | trlsfval | ⊢ ( Trails ‘ 𝐺 ) = { 〈 𝑓 , 𝑝 〉 ∣ ( 𝑓 ( Walks ‘ 𝐺 ) 𝑝 ∧ Fun ◡ 𝑓 ) } |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | biidd | ⊢ ( 𝑔 = 𝐺 → ( Fun ◡ 𝑓 ↔ Fun ◡ 𝑓 ) ) | |
| 2 | df-trls | ⊢ Trails = ( 𝑔 ∈ V ↦ { 〈 𝑓 , 𝑝 〉 ∣ ( 𝑓 ( Walks ‘ 𝑔 ) 𝑝 ∧ Fun ◡ 𝑓 ) } ) | |
| 3 | 1 2 | fvmptopab | ⊢ ( Trails ‘ 𝐺 ) = { 〈 𝑓 , 𝑝 〉 ∣ ( 𝑓 ( Walks ‘ 𝐺 ) 𝑝 ∧ Fun ◡ 𝑓 ) } |