Description: The surreal numbers are a proper class. (Contributed by Scott Fenton, 16-Jun-2011)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | noprc | ⊢ ¬ No ∈ V |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | onprc | ⊢ ¬ On ∈ V | |
| 2 | bdayfo | ⊢ bday : No –onto→ On | |
| 3 | focdmex | ⊢ ( No ∈ V → ( bday : No –onto→ On → On ∈ V ) ) | |
| 4 | 2 3 | mpi | ⊢ ( No ∈ V → On ∈ V ) |
| 5 | 1 4 | mto | ⊢ ¬ No ∈ V |