Metamath Proof Explorer


Theorem ondif1

Description: Two ways to say that A is a nonzero ordinal number. (Contributed by Mario Carneiro, 21-May-2015)

Ref Expression
Assertion ondif1 A On 1 𝑜 A On A

Proof

Step Hyp Ref Expression
1 dif1o A On 1 𝑜 A On A
2 on0eln0 A On A A
3 2 pm5.32i A On A A On A
4 1 3 bitr4i A On 1 𝑜 A On A