Metamath Proof Explorer

Theorem 4z

Description: 4 is an integer. (Contributed by BJ, 26-Mar-2020)

Ref Expression
Assertion 4z 
|- 4 e. ZZ

Proof

Step Hyp Ref Expression
1 4nn 
 |-  4 e. NN
2 1 nnzi 
 |-  4 e. ZZ