Description: Universal class equality in terms of empty difference. (Contributed by NM, 17-Sep-2003)
Ref | Expression | ||
---|---|---|---|
Assertion | vdif0 | ⊢ ( 𝐴 = V ↔ ( V ∖ 𝐴 ) = ∅ ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vss | ⊢ ( V ⊆ 𝐴 ↔ 𝐴 = V ) | |
2 | ssdif0 | ⊢ ( V ⊆ 𝐴 ↔ ( V ∖ 𝐴 ) = ∅ ) | |
3 | 1 2 | bitr3i | ⊢ ( 𝐴 = V ↔ ( V ∖ 𝐴 ) = ∅ ) |