Description: If the input class has elements, then the Scott's trick set is not empty. (Contributed by BTernaryTau, 23-Aug-2026)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | elscottn0 | ⊢ ( 𝐴 ∈ 𝐵 → Scott 𝐵 ≠ ∅ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ne0i | ⊢ ( 𝐴 ∈ 𝐵 → 𝐵 ≠ ∅ ) | |
| 2 | scott0b | ⊢ ( 𝐵 = ∅ ↔ Scott 𝐵 = ∅ ) | |
| 3 | 2 | necon3bii | ⊢ ( 𝐵 ≠ ∅ ↔ Scott 𝐵 ≠ ∅ ) |
| 4 | 1 3 | sylib | ⊢ ( 𝐴 ∈ 𝐵 → Scott 𝐵 ≠ ∅ ) |