Metamath Proof Explorer

Theorem 1zzd

Description: One is an integer, deduction form. (Contributed by David A. Wheeler, 6-Dec-2018)

Ref Expression
Assertion 1zzd 
|- ( ph -> 1 e. ZZ )

Proof

Step Hyp Ref Expression
1 1z 
 |-  1 e. ZZ
2 1 a1i 
 |-  ( ph -> 1 e. ZZ )