Description: Define addition on 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, 26-Aug-1995) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-pli | |- +N = ( +o |` ( N. X. N. ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cpli | |- +N |
|
| 1 | coa | |- +o |
|
| 2 | cnpi | |- N. |
|
| 3 | 2 2 | cxp | |- ( N. X. N. ) |
| 4 | 1 3 | cres | |- ( +o |` ( N. X. N. ) ) |
| 5 | 0 4 | wceq | |- +N = ( +o |` ( N. X. N. ) ) |