Metamath Proof Explorer


Theorem noprc

Description: The surreal numbers are a proper class. (Contributed by Scott Fenton, 16-Jun-2011)

Ref Expression
Assertion noprc ¬ No ∈ V

Proof

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