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Definition df-ni 9654
Description: Define the class of positive integers. This is a "temporary" set used in the construction of complex numbers df-c 9902, 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
StepHypRef Expression
1 cnpi 9626 . 2 class N
2 com 7027 . . 3 class ω
3 c0 3897 . . . 4 class
43csn 4155 . . 3 class {∅}
52, 4cdif 3557 . 2 class (ω ∖ {∅})
61, 5wceq 1480 1 wff N = (ω ∖ {∅})
Colors of variables: wff setvar class
This definition is referenced by:  elni  9658  pinn  9660  niex  9663  ltsopi  9670  dmaddpi  9672  dmmulpi  9673  wuncn  9951
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