| Step | Hyp | Ref | Expression | 
						
							| 1 |  | trlres.v | ⊢ 𝑉  =  ( Vtx ‘ 𝐺 ) | 
						
							| 2 |  | trlres.i | ⊢ 𝐼  =  ( iEdg ‘ 𝐺 ) | 
						
							| 3 |  | trlres.d | ⊢ ( 𝜑  →  𝐹 ( Trails ‘ 𝐺 ) 𝑃 ) | 
						
							| 4 |  | trlres.n | ⊢ ( 𝜑  →  𝑁  ∈  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) | 
						
							| 5 |  | trlres.h | ⊢ 𝐻  =  ( 𝐹  prefix  𝑁 ) | 
						
							| 6 | 2 | trlf1 | ⊢ ( 𝐹 ( Trails ‘ 𝐺 ) 𝑃  →  𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom  𝐼 ) | 
						
							| 7 | 3 6 | syl | ⊢ ( 𝜑  →  𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom  𝐼 ) | 
						
							| 8 |  | elfzouz2 | ⊢ ( 𝑁  ∈  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  →  ( ♯ ‘ 𝐹 )  ∈  ( ℤ≥ ‘ 𝑁 ) ) | 
						
							| 9 |  | fzoss2 | ⊢ ( ( ♯ ‘ 𝐹 )  ∈  ( ℤ≥ ‘ 𝑁 )  →  ( 0 ..^ 𝑁 )  ⊆  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) | 
						
							| 10 | 4 8 9 | 3syl | ⊢ ( 𝜑  →  ( 0 ..^ 𝑁 )  ⊆  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) | 
						
							| 11 |  | f1ores | ⊢ ( ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) –1-1→ dom  𝐼  ∧  ( 0 ..^ 𝑁 )  ⊆  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) )  →  ( 𝐹  ↾  ( 0 ..^ 𝑁 ) ) : ( 0 ..^ 𝑁 ) –1-1-onto→ ( 𝐹  “  ( 0 ..^ 𝑁 ) ) ) | 
						
							| 12 | 7 10 11 | syl2anc | ⊢ ( 𝜑  →  ( 𝐹  ↾  ( 0 ..^ 𝑁 ) ) : ( 0 ..^ 𝑁 ) –1-1-onto→ ( 𝐹  “  ( 0 ..^ 𝑁 ) ) ) | 
						
							| 13 |  | trliswlk | ⊢ ( 𝐹 ( Trails ‘ 𝐺 ) 𝑃  →  𝐹 ( Walks ‘ 𝐺 ) 𝑃 ) | 
						
							| 14 | 2 | wlkf | ⊢ ( 𝐹 ( Walks ‘ 𝐺 ) 𝑃  →  𝐹  ∈  Word  dom  𝐼 ) | 
						
							| 15 | 3 13 14 | 3syl | ⊢ ( 𝜑  →  𝐹  ∈  Word  dom  𝐼 ) | 
						
							| 16 |  | fzossfz | ⊢ ( 0 ..^ ( ♯ ‘ 𝐹 ) )  ⊆  ( 0 ... ( ♯ ‘ 𝐹 ) ) | 
						
							| 17 | 16 4 | sselid | ⊢ ( 𝜑  →  𝑁  ∈  ( 0 ... ( ♯ ‘ 𝐹 ) ) ) | 
						
							| 18 |  | pfxres | ⊢ ( ( 𝐹  ∈  Word  dom  𝐼  ∧  𝑁  ∈  ( 0 ... ( ♯ ‘ 𝐹 ) ) )  →  ( 𝐹  prefix  𝑁 )  =  ( 𝐹  ↾  ( 0 ..^ 𝑁 ) ) ) | 
						
							| 19 | 15 17 18 | syl2anc | ⊢ ( 𝜑  →  ( 𝐹  prefix  𝑁 )  =  ( 𝐹  ↾  ( 0 ..^ 𝑁 ) ) ) | 
						
							| 20 | 5 19 | eqtrid | ⊢ ( 𝜑  →  𝐻  =  ( 𝐹  ↾  ( 0 ..^ 𝑁 ) ) ) | 
						
							| 21 | 5 | fveq2i | ⊢ ( ♯ ‘ 𝐻 )  =  ( ♯ ‘ ( 𝐹  prefix  𝑁 ) ) | 
						
							| 22 |  | elfzofz | ⊢ ( 𝑁  ∈  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  →  𝑁  ∈  ( 0 ... ( ♯ ‘ 𝐹 ) ) ) | 
						
							| 23 | 4 22 | syl | ⊢ ( 𝜑  →  𝑁  ∈  ( 0 ... ( ♯ ‘ 𝐹 ) ) ) | 
						
							| 24 |  | pfxlen | ⊢ ( ( 𝐹  ∈  Word  dom  𝐼  ∧  𝑁  ∈  ( 0 ... ( ♯ ‘ 𝐹 ) ) )  →  ( ♯ ‘ ( 𝐹  prefix  𝑁 ) )  =  𝑁 ) | 
						
							| 25 | 15 23 24 | syl2anc | ⊢ ( 𝜑  →  ( ♯ ‘ ( 𝐹  prefix  𝑁 ) )  =  𝑁 ) | 
						
							| 26 | 21 25 | eqtrid | ⊢ ( 𝜑  →  ( ♯ ‘ 𝐻 )  =  𝑁 ) | 
						
							| 27 | 26 | oveq2d | ⊢ ( 𝜑  →  ( 0 ..^ ( ♯ ‘ 𝐻 ) )  =  ( 0 ..^ 𝑁 ) ) | 
						
							| 28 |  | wrdf | ⊢ ( 𝐹  ∈  Word  dom  𝐼  →  𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ⟶ dom  𝐼 ) | 
						
							| 29 |  | fimass | ⊢ ( 𝐹 : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ⟶ dom  𝐼  →  ( 𝐹  “  ( 0 ..^ 𝑁 ) )  ⊆  dom  𝐼 ) | 
						
							| 30 | 14 28 29 | 3syl | ⊢ ( 𝐹 ( Walks ‘ 𝐺 ) 𝑃  →  ( 𝐹  “  ( 0 ..^ 𝑁 ) )  ⊆  dom  𝐼 ) | 
						
							| 31 | 3 13 30 | 3syl | ⊢ ( 𝜑  →  ( 𝐹  “  ( 0 ..^ 𝑁 ) )  ⊆  dom  𝐼 ) | 
						
							| 32 |  | ssdmres | ⊢ ( ( 𝐹  “  ( 0 ..^ 𝑁 ) )  ⊆  dom  𝐼  ↔  dom  ( 𝐼  ↾  ( 𝐹  “  ( 0 ..^ 𝑁 ) ) )  =  ( 𝐹  “  ( 0 ..^ 𝑁 ) ) ) | 
						
							| 33 | 31 32 | sylib | ⊢ ( 𝜑  →  dom  ( 𝐼  ↾  ( 𝐹  “  ( 0 ..^ 𝑁 ) ) )  =  ( 𝐹  “  ( 0 ..^ 𝑁 ) ) ) | 
						
							| 34 | 20 27 33 | f1oeq123d | ⊢ ( 𝜑  →  ( 𝐻 : ( 0 ..^ ( ♯ ‘ 𝐻 ) ) –1-1-onto→ dom  ( 𝐼  ↾  ( 𝐹  “  ( 0 ..^ 𝑁 ) ) )  ↔  ( 𝐹  ↾  ( 0 ..^ 𝑁 ) ) : ( 0 ..^ 𝑁 ) –1-1-onto→ ( 𝐹  “  ( 0 ..^ 𝑁 ) ) ) ) | 
						
							| 35 | 12 34 | mpbird | ⊢ ( 𝜑  →  𝐻 : ( 0 ..^ ( ♯ ‘ 𝐻 ) ) –1-1-onto→ dom  ( 𝐼  ↾  ( 𝐹  “  ( 0 ..^ 𝑁 ) ) ) ) |