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Description: Express the range of a subword. Stronger version of swrdrn2 . (Contributed by Thierry Arnoux, 13-Dec-2023)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | swrdrn3 | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ran ( 𝑊 substr 〈 𝑀 , 𝑁 〉 ) = ( 𝑊 “ ( 𝑀 ..^ 𝑁 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpr | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) → 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) | |
| 2 | simpl3 | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) → 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) | |
| 3 | 2 | elfzelzd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) → 𝑁 ∈ ℤ ) |
| 4 | simpl2 | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) → 𝑀 ∈ ( 0 ... 𝑁 ) ) | |
| 5 | 4 | elfzelzd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) → 𝑀 ∈ ℤ ) |
| 6 | fzoaddel2 | ⊢ ( ( 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ∧ 𝑁 ∈ ℤ ∧ 𝑀 ∈ ℤ ) → ( 𝑖 + 𝑀 ) ∈ ( 𝑀 ..^ 𝑁 ) ) | |
| 7 | 1 3 5 6 | syl3anc | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) → ( 𝑖 + 𝑀 ) ∈ ( 𝑀 ..^ 𝑁 ) ) |
| 8 | simpr | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) | |
| 9 | simpl2 | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑀 ∈ ( 0 ... 𝑁 ) ) | |
| 10 | 9 | elfzelzd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑀 ∈ ℤ ) |
| 11 | 10 | zcnd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑀 ∈ ℂ ) |
| 12 | simpl3 | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) | |
| 13 | 12 | elfzelzd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑁 ∈ ℤ ) |
| 14 | 13 | zcnd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑁 ∈ ℂ ) |
| 15 | 11 14 | pncan3d | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → ( 𝑀 + ( 𝑁 − 𝑀 ) ) = 𝑁 ) |
| 16 | 15 | oveq2d | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → ( 𝑀 ..^ ( 𝑀 + ( 𝑁 − 𝑀 ) ) ) = ( 𝑀 ..^ 𝑁 ) ) |
| 17 | 8 16 | eleqtrrd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑗 ∈ ( 𝑀 ..^ ( 𝑀 + ( 𝑁 − 𝑀 ) ) ) ) |
| 18 | 13 10 | zsubcld | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → ( 𝑁 − 𝑀 ) ∈ ℤ ) |
| 19 | fzosubel3 | ⊢ ( ( 𝑗 ∈ ( 𝑀 ..^ ( 𝑀 + ( 𝑁 − 𝑀 ) ) ) ∧ ( 𝑁 − 𝑀 ) ∈ ℤ ) → ( 𝑗 − 𝑀 ) ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) | |
| 20 | 17 18 19 | syl2anc | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → ( 𝑗 − 𝑀 ) ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ) |
| 21 | simpr | ⊢ ( ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) ∧ 𝑖 = ( 𝑗 − 𝑀 ) ) → 𝑖 = ( 𝑗 − 𝑀 ) ) | |
| 22 | 21 | oveq1d | ⊢ ( ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) ∧ 𝑖 = ( 𝑗 − 𝑀 ) ) → ( 𝑖 + 𝑀 ) = ( ( 𝑗 − 𝑀 ) + 𝑀 ) ) |
| 23 | 22 | eqeq2d | ⊢ ( ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) ∧ 𝑖 = ( 𝑗 − 𝑀 ) ) → ( 𝑗 = ( 𝑖 + 𝑀 ) ↔ 𝑗 = ( ( 𝑗 − 𝑀 ) + 𝑀 ) ) ) |
| 24 | fzossz | ⊢ ( 𝑀 ..^ 𝑁 ) ⊆ ℤ | |
| 25 | 24 8 | sselid | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑗 ∈ ℤ ) |
| 26 | 25 | zcnd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑗 ∈ ℂ ) |
| 27 | 26 11 | npcand | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → ( ( 𝑗 − 𝑀 ) + 𝑀 ) = 𝑗 ) |
| 28 | 27 | eqcomd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → 𝑗 = ( ( 𝑗 − 𝑀 ) + 𝑀 ) ) |
| 29 | 20 23 28 | rspcedvd | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ) → ∃ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) 𝑗 = ( 𝑖 + 𝑀 ) ) |
| 30 | eqcom | ⊢ ( 𝑦 = ( 𝑊 ‘ 𝑗 ) ↔ ( 𝑊 ‘ 𝑗 ) = 𝑦 ) | |
| 31 | simpr | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 = ( 𝑖 + 𝑀 ) ) → 𝑗 = ( 𝑖 + 𝑀 ) ) | |
| 32 | 31 | fveq2d | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 = ( 𝑖 + 𝑀 ) ) → ( 𝑊 ‘ 𝑗 ) = ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) |
| 33 | 32 | eqeq2d | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 = ( 𝑖 + 𝑀 ) ) → ( 𝑦 = ( 𝑊 ‘ 𝑗 ) ↔ 𝑦 = ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) ) |
| 34 | 30 33 | bitr3id | ⊢ ( ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) ∧ 𝑗 = ( 𝑖 + 𝑀 ) ) → ( ( 𝑊 ‘ 𝑗 ) = 𝑦 ↔ 𝑦 = ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) ) |
| 35 | 7 29 34 | rexxfrd | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( ∃ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ( 𝑊 ‘ 𝑗 ) = 𝑦 ↔ ∃ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) 𝑦 = ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) ) |
| 36 | eqid | ⊢ ( 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ↦ ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) = ( 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ↦ ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) | |
| 37 | fvex | ⊢ ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ∈ V | |
| 38 | 36 37 | elrnmpti | ⊢ ( 𝑦 ∈ ran ( 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ↦ ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) ↔ ∃ 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) 𝑦 = ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) |
| 39 | 35 38 | bitr4di | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( ∃ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ( 𝑊 ‘ 𝑗 ) = 𝑦 ↔ 𝑦 ∈ ran ( 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ↦ ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) ) ) |
| 40 | wrdf | ⊢ ( 𝑊 ∈ Word 𝑉 → 𝑊 : ( 0 ..^ ( ♯ ‘ 𝑊 ) ) ⟶ 𝑉 ) | |
| 41 | 40 | 3ad2ant1 | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → 𝑊 : ( 0 ..^ ( ♯ ‘ 𝑊 ) ) ⟶ 𝑉 ) |
| 42 | 41 | ffnd | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → 𝑊 Fn ( 0 ..^ ( ♯ ‘ 𝑊 ) ) ) |
| 43 | elfzuz | ⊢ ( 𝑀 ∈ ( 0 ... 𝑁 ) → 𝑀 ∈ ( ℤ≥ ‘ 0 ) ) | |
| 44 | 43 | 3ad2ant2 | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → 𝑀 ∈ ( ℤ≥ ‘ 0 ) ) |
| 45 | fzoss1 | ⊢ ( 𝑀 ∈ ( ℤ≥ ‘ 0 ) → ( 𝑀 ..^ 𝑁 ) ⊆ ( 0 ..^ 𝑁 ) ) | |
| 46 | 44 45 | syl | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( 𝑀 ..^ 𝑁 ) ⊆ ( 0 ..^ 𝑁 ) ) |
| 47 | elfzuz3 | ⊢ ( 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) → ( ♯ ‘ 𝑊 ) ∈ ( ℤ≥ ‘ 𝑁 ) ) | |
| 48 | 47 | 3ad2ant3 | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( ♯ ‘ 𝑊 ) ∈ ( ℤ≥ ‘ 𝑁 ) ) |
| 49 | fzoss2 | ⊢ ( ( ♯ ‘ 𝑊 ) ∈ ( ℤ≥ ‘ 𝑁 ) → ( 0 ..^ 𝑁 ) ⊆ ( 0 ..^ ( ♯ ‘ 𝑊 ) ) ) | |
| 50 | 48 49 | syl | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( 0 ..^ 𝑁 ) ⊆ ( 0 ..^ ( ♯ ‘ 𝑊 ) ) ) |
| 51 | 46 50 | sstrd | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( 𝑀 ..^ 𝑁 ) ⊆ ( 0 ..^ ( ♯ ‘ 𝑊 ) ) ) |
| 52 | 42 51 | fvelimabd | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( 𝑦 ∈ ( 𝑊 “ ( 𝑀 ..^ 𝑁 ) ) ↔ ∃ 𝑗 ∈ ( 𝑀 ..^ 𝑁 ) ( 𝑊 ‘ 𝑗 ) = 𝑦 ) ) |
| 53 | swrdval2 | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( 𝑊 substr 〈 𝑀 , 𝑁 〉 ) = ( 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ↦ ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) ) | |
| 54 | 53 | rneqd | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ran ( 𝑊 substr 〈 𝑀 , 𝑁 〉 ) = ran ( 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ↦ ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) ) |
| 55 | 54 | eleq2d | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( 𝑦 ∈ ran ( 𝑊 substr 〈 𝑀 , 𝑁 〉 ) ↔ 𝑦 ∈ ran ( 𝑖 ∈ ( 0 ..^ ( 𝑁 − 𝑀 ) ) ↦ ( 𝑊 ‘ ( 𝑖 + 𝑀 ) ) ) ) ) |
| 56 | 39 52 55 | 3bitr4rd | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( 𝑦 ∈ ran ( 𝑊 substr 〈 𝑀 , 𝑁 〉 ) ↔ 𝑦 ∈ ( 𝑊 “ ( 𝑀 ..^ 𝑁 ) ) ) ) |
| 57 | 56 | eqrdv | ⊢ ( ( 𝑊 ∈ Word 𝑉 ∧ 𝑀 ∈ ( 0 ... 𝑁 ) ∧ 𝑁 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ran ( 𝑊 substr 〈 𝑀 , 𝑁 〉 ) = ( 𝑊 “ ( 𝑀 ..^ 𝑁 ) ) ) |