Description: All sets are well-orderable under choice. (Contributed by Stefan O'Rear, 28-Feb-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | numth3 | ⊢ ( 𝐴 ∈ 𝑉 → 𝐴 ∈ dom card ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elex | ⊢ ( 𝐴 ∈ 𝑉 → 𝐴 ∈ V ) | |
| 2 | cardeqv | ⊢ dom card = V | |
| 3 | 1 2 | eleqtrrdi | ⊢ ( 𝐴 ∈ 𝑉 → 𝐴 ∈ dom card ) |