Definition df-ni 10816

Description: Define the class of positive integers. This is a "temporary" set used in the construction of complex numbers df-c 11065, and is intended to be used only by the construction. (Contributed by NM, 15-Aug-1995.) (New usage is discouraged.)

Assertion

Ref	Expression
df-ni	⊢ N = (ω ∖ {∅})

Detailed syntax breakdown of Definition df-ni

Step	Hyp	Ref	Expression
1		cnpi 10788	. 2 class N
2		com 7831	. . 3 class ω
3		c0 4276	. . . 4 class ∅
4	3	csn 4572	. . 3 class {∅}
5	2, 4	cdif 3892	. 2 class (ω ∖ {∅})
6	1, 5	wceq 1550	1 wff N = (ω ∖ {∅})

This definition is referenced by:  elni  10820  pinn  10822  niex  10825  ltsopi  10832  dmaddpi  10834  dmmulpi  10835  wuncn  11114