Metamath Proof Explorer

Theorem nn0zd

Description: A nonnegative integer is an integer. (Contributed by Mario Carneiro, 28-May-2016)

Ref Expression
Hypothesis nn0zd.1 
|- ( ph -> A e. NN0 )
Assertion nn0zd 
|- ( ph -> A e. ZZ )

Proof

Step Hyp Ref Expression
1 nn0zd.1 
 |-  ( ph -> A e. NN0 )
2 nn0ssz 
 |-  NN0 C_ ZZ
3 2 1 sselid 
 |-  ( ph -> A e. ZZ )