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Description: The set of words over a set is a set, bidirectional version. (Contributed by Mario Carneiro, 26-Feb-2016) (Proof shortened by AV, 23-Nov-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | wrdexb | ⊢ ( 𝑆 ∈ V ↔ Word 𝑆 ∈ V ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | wrdexg | ⊢ ( 𝑆 ∈ V → Word 𝑆 ∈ V ) | |
| 2 | opex | ⊢ 〈 0 , 𝑠 〉 ∈ V | |
| 3 | 2 | snid | ⊢ 〈 0 , 𝑠 〉 ∈ { 〈 0 , 𝑠 〉 } |
| 4 | snopiswrd | ⊢ ( 𝑠 ∈ 𝑆 → { 〈 0 , 𝑠 〉 } ∈ Word 𝑆 ) | |
| 5 | elunii | ⊢ ( ( 〈 0 , 𝑠 〉 ∈ { 〈 0 , 𝑠 〉 } ∧ { 〈 0 , 𝑠 〉 } ∈ Word 𝑆 ) → 〈 0 , 𝑠 〉 ∈ ∪ Word 𝑆 ) | |
| 6 | 3 4 5 | sylancr | ⊢ ( 𝑠 ∈ 𝑆 → 〈 0 , 𝑠 〉 ∈ ∪ Word 𝑆 ) |
| 7 | c0ex | ⊢ 0 ∈ V | |
| 8 | vex | ⊢ 𝑠 ∈ V | |
| 9 | 7 8 | opeluu | ⊢ ( 〈 0 , 𝑠 〉 ∈ ∪ Word 𝑆 → ( 0 ∈ ∪ ∪ ∪ Word 𝑆 ∧ 𝑠 ∈ ∪ ∪ ∪ Word 𝑆 ) ) |
| 10 | 6 9 | syl | ⊢ ( 𝑠 ∈ 𝑆 → ( 0 ∈ ∪ ∪ ∪ Word 𝑆 ∧ 𝑠 ∈ ∪ ∪ ∪ Word 𝑆 ) ) |
| 11 | 10 | simprd | ⊢ ( 𝑠 ∈ 𝑆 → 𝑠 ∈ ∪ ∪ ∪ Word 𝑆 ) |
| 12 | 11 | ssriv | ⊢ 𝑆 ⊆ ∪ ∪ ∪ Word 𝑆 |
| 13 | uniexg | ⊢ ( Word 𝑆 ∈ V → ∪ Word 𝑆 ∈ V ) | |
| 14 | uniexg | ⊢ ( ∪ Word 𝑆 ∈ V → ∪ ∪ Word 𝑆 ∈ V ) | |
| 15 | uniexg | ⊢ ( ∪ ∪ Word 𝑆 ∈ V → ∪ ∪ ∪ Word 𝑆 ∈ V ) | |
| 16 | 13 14 15 | 3syl | ⊢ ( Word 𝑆 ∈ V → ∪ ∪ ∪ Word 𝑆 ∈ V ) |
| 17 | ssexg | ⊢ ( ( 𝑆 ⊆ ∪ ∪ ∪ Word 𝑆 ∧ ∪ ∪ ∪ Word 𝑆 ∈ V ) → 𝑆 ∈ V ) | |
| 18 | 12 16 17 | sylancr | ⊢ ( Word 𝑆 ∈ V → 𝑆 ∈ V ) |
| 19 | 1 18 | impbii | ⊢ ( 𝑆 ∈ V ↔ Word 𝑆 ∈ V ) |