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Mirrors > Home > MPE Home > Th. List > df-ni | Structured version Visualization version GIF version |
Description: Define the class of positive integers. This is a "temporary" set used in the construction of complex numbers df-c 10735, and is intended to be used only by the construction. (Contributed by NM, 15-Aug-1995.) (New usage is discouraged.) |
Ref | Expression |
---|---|
df-ni | ⊢ N = (ω ∖ {∅}) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cnpi 10458 | . 2 class N | |
2 | com 7644 | . . 3 class ω | |
3 | c0 4237 | . . . 4 class ∅ | |
4 | 3 | csn 4541 | . . 3 class {∅} |
5 | 2, 4 | cdif 3863 | . 2 class (ω ∖ {∅}) |
6 | 1, 5 | wceq 1543 | 1 wff N = (ω ∖ {∅}) |
Colors of variables: wff setvar class |
This definition is referenced by: elni 10490 pinn 10492 niex 10495 ltsopi 10502 dmaddpi 10504 dmmulpi 10505 wuncn 10784 |
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