Definition df-ni 6288

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

Assertion

Ref	Expression
df-ni	⊢ N = (𝜔 ∖ {∅})

Detailed syntax breakdown of Definition df-ni

Step	Hyp	Ref	Expression
1		cnpi 6256	. 2 class N
2		com 4256	. . 3 class 𝜔
3		c0 3218	. . . 4 class ∅
4	3	csn 3367	. . 3 class {∅}
5	2, 4	cdif 2908	. 2 class (𝜔 ∖ {∅})
6	1, 5	wceq 1242	1 wff N = (𝜔 ∖ {∅})

This definition is referenced by:  elni  6292  pinn  6293  niex  6296  dmaddpi  6309  dmmulpi  6310