Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - add the Axiom of Power Sets
Ordinals
onordi
Next ⟩
ontrci
Metamath Proof Explorer
Ascii
Unicode
Theorem
onordi
Description:
An ordinal number is an ordinal class.
(Contributed by
NM
, 11-Jun-1994)
Ref
Expression
Hypothesis
on.1
⊢
A
∈
On
Assertion
onordi
⊢
Ord
⁡
A
Proof
Step
Hyp
Ref
Expression
1
on.1
⊢
A
∈
On
2
eloni
⊢
A
∈
On
→
Ord
⁡
A
3
1
2
ax-mp
⊢
Ord
⁡
A