Theorem oddz

Description: An odd number is an integer. (Contributed by AV, 14-Jun-2020)

	Ref	Expression
Assertion	oddz	|- ( Z e. Odd -> Z e. ZZ )

Proof

Step	Hyp	Ref	Expression
1		isodd	|- ( Z e. Odd <-> ( Z e. ZZ /\ ( ( Z + 1 ) / 2 ) e. ZZ ) )
2	1	simplbi	|- ( Z e. Odd -> Z e. ZZ )