| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpr | ⊢ ( ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  ∧  𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 )  →  𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 ) | 
						
							| 2 |  | fzossfz | ⊢ ( 0 ..^ ( ♯ ‘ 𝐹 ) )  ⊆  ( 0 ... ( ♯ ‘ 𝐹 ) ) | 
						
							| 3 |  | fssres | ⊢ ( ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉  ∧  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  ⊆  ( 0 ... ( ♯ ‘ 𝐹 ) ) )  →  ( 𝑃  ↾  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 ) | 
						
							| 4 | 1 2 3 | sylancl | ⊢ ( ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  ∧  𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 )  →  ( 𝑃  ↾  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 ) | 
						
							| 5 | 4 | ex | ⊢ ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  →  ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉  →  ( 𝑃  ↾  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 ) ) | 
						
							| 6 |  | lencl | ⊢ ( 𝐹  ∈  Word  𝑆  →  ( ♯ ‘ 𝐹 )  ∈  ℕ0 ) | 
						
							| 7 | 6 | nn0zd | ⊢ ( 𝐹  ∈  Word  𝑆  →  ( ♯ ‘ 𝐹 )  ∈  ℤ ) | 
						
							| 8 |  | fzoval | ⊢ ( ( ♯ ‘ 𝐹 )  ∈  ℤ  →  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  =  ( 0 ... ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) | 
						
							| 9 | 7 8 | syl | ⊢ ( 𝐹  ∈  Word  𝑆  →  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  =  ( 0 ... ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) | 
						
							| 10 | 9 | adantr | ⊢ ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  →  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  =  ( 0 ... ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) | 
						
							| 11 |  | wrdred1hash | ⊢ ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  →  ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) )  =  ( ( ♯ ‘ 𝐹 )  −  1 ) ) | 
						
							| 12 |  | oveq2 | ⊢ ( ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) )  =  ( ( ♯ ‘ 𝐹 )  −  1 )  →  ( 0 ... ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) )  =  ( 0 ... ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) | 
						
							| 13 | 12 | eqeq2d | ⊢ ( ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) )  =  ( ( ♯ ‘ 𝐹 )  −  1 )  →  ( ( 0 ..^ ( ♯ ‘ 𝐹 ) )  =  ( 0 ... ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) )  ↔  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  =  ( 0 ... ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) | 
						
							| 14 | 11 13 | syl | ⊢ ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  →  ( ( 0 ..^ ( ♯ ‘ 𝐹 ) )  =  ( 0 ... ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) )  ↔  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  =  ( 0 ... ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) | 
						
							| 15 | 10 14 | mpbird | ⊢ ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  →  ( 0 ..^ ( ♯ ‘ 𝐹 ) )  =  ( 0 ... ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) ) ) | 
						
							| 16 | 15 | feq2d | ⊢ ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  →  ( ( 𝑃  ↾  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) : ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉  ↔  ( 𝑃  ↾  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) : ( 0 ... ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) ) ⟶ 𝑉 ) ) | 
						
							| 17 | 5 16 | sylibd | ⊢ ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 ) )  →  ( 𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉  →  ( 𝑃  ↾  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) : ( 0 ... ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) ) ⟶ 𝑉 ) ) | 
						
							| 18 | 17 | 3impia | ⊢ ( ( 𝐹  ∈  Word  𝑆  ∧  1  ≤  ( ♯ ‘ 𝐹 )  ∧  𝑃 : ( 0 ... ( ♯ ‘ 𝐹 ) ) ⟶ 𝑉 )  →  ( 𝑃  ↾  ( 0 ..^ ( ♯ ‘ 𝐹 ) ) ) : ( 0 ... ( ♯ ‘ ( 𝐹  ↾  ( 0 ..^ ( ( ♯ ‘ 𝐹 )  −  1 ) ) ) ) ) ⟶ 𝑉 ) |