Definition df-ni 4987

Description: Define the class of positive integers. This is a "temporary" set used in the construction of complex numbers df-c 5227, 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 4959	. 2 class N.
2		com 3128	. . 3 class om
3		c0 2278	. . . 4 class (/)
4	3	csn 2407	. . 3 class {(/)}
5	2, 4	cdif 2042	. 2 class (om \ {(/)})
6	1, 5	wceq 955	1 wff N. = (om \ {(/)})

This definition is referenced by:  elni 4991  pinn 4993  niex 4996  dmaddpi 5005  dmmulpi 5006

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