Theorem 6onn

Description: The ordinal 6 is a natural number. (Contributed by BTernaryTau, 4-Sep-2026)

	Ref	Expression
Assertion	6onn	Could not format assertion : No typesetting found for |- 6o e. _om with typecode |-

Proof

Step	Hyp	Ref	Expression
1		df-6o	Could not format 6o = suc 5o : No typesetting found for |- 6o = suc 5o with typecode |-
2		5onn	Could not format 5o e. _om : No typesetting found for |- 5o e. _om with typecode |-
3		peano2	Could not format ( 5o e. _om -> suc 5o e. _om ) : No typesetting found for |- ( 5o e. _om -> suc 5o e. _om ) with typecode |-
4	2 3	ax-mp	Could not format suc 5o e. _om : No typesetting found for |- suc 5o e. _om with typecode |-
5	1 4	eqeltri	Could not format 6o e. _om : No typesetting found for |- 6o e. _om with typecode |-