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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	$⊢ 𝑵 = ω ∖ \{\emptyset\}$

Detailed syntax breakdown

Step	Hyp	Ref	Expression
0		cnpi	$class 𝑵$
1		com	$class ω$
2		c0	$class \emptyset$
3	2	csn	$class \{\emptyset\}$
4	1 3	cdif	$class (ω ∖ \{\emptyset\})$
5	0 4	wceq	$wff 𝑵 = ω ∖ \{\emptyset\}$