Definition df-ni 4972

Description: Define the class of positive integers. This is a "temporary" set used in the construction of complex numbers df-c 5212, and is intended to be used only by the construction.

Assertion

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

Detailed syntax breakdown of Definition df-ni

Step	Hyp	Ref	Expression
1		cnpi 4944	. 2 class N.
2		com 3121	. . 3 class om
3		c0 2270	. . . 4 class (/)
4	3	csn 2399	. . 3 class {(/)}
5	2, 4	cdif 2034	. 2 class (om \ {(/)})
6	1, 5	wceq 953	1 wff N. = (om \ {(/)})

This definition is referenced by:  elni 4976  pinn 4978  niex 4981  dmaddpi 4990  dmmulpi 4991

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