Metamath Proof Explorer


Definition df-ni

Description: Define the class of positive integers. This is a "temporary" set used in the construction of complex numbers df-c , and is intended to be used only by the construction. (Contributed by NM, 15-Aug-1995) (New usage is discouraged.)

Ref Expression
Assertion df-ni
|- N. = ( _om \ { (/) } )

Detailed syntax breakdown

Step Hyp Ref Expression
0 cnpi
 |-  N.
1 com
 |-  _om
2 c0
 |-  (/)
3 2 csn
 |-  { (/) }
4 1 3 cdif
 |-  ( _om \ { (/) } )
5 0 4 wceq
 |-  N. = ( _om \ { (/) } )