Metamath Proof Explorer


Definition df-mi

Description: Define multiplication 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-mi 𝑵=𝑜𝑵×𝑵

Detailed syntax breakdown

Step Hyp Ref Expression
0 cmi class𝑵
1 comu class𝑜
2 cnpi class𝑵
3 2 2 cxp class𝑵×𝑵
4 1 3 cres class𝑜𝑵×𝑵
5 0 4 wceq wff𝑵=𝑜𝑵×𝑵