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Definition df-ni 9882
Description: Define the class of positive integers. This is a "temporary" set used in the construction of complex numbers df-c 10130, 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 9854 . 2 class N
2 com 7226 . . 3 class ω
3 c0 4054 . . . 4 class
43csn 4317 . . 3 class {∅}
52, 4cdif 3708 . 2 class (ω ∖ {∅})
61, 5wceq 1628 1 wff N = (ω ∖ {∅})
Colors of variables: wff setvar class
This definition is referenced by:  elni  9886  pinn  9888  niex  9891  ltsopi  9898  dmaddpi  9900  dmmulpi  9901  wuncn  10179
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