In fact, there are ternary numbers, quaternary numbers, n-ary numbers and even infinite numbers. Look for the theory of multivariate and infinite numbers on the internet. Please look at the paper (originally published in the Journal of Middle School Mathematics of Qufu Normal University) on the ternary number theory of spherical coordinates reprinted on the website of the Curriculum Institute of People's Education Publishing House. Ternary number other than complex number:/gzsx/jszx _1/jxyj/gzsxjscg/2012/t 20101227 _ 993192.htm generalized spherical coordinate n. Jszx _1/jxyj/gzsxjscg/2012/t 201010 _ 985645.htm's proof of algebraic fundamental theorem in n-dimensional space: proof of algebraic fundamental theorem in high-dimensional space:/gzsx/0. Jxyj/gzsxjscg/2065433 published a new paper "The New Definition of Ternary Numbers" in China Scientific Papers, which was supported by the National Natural Science Foundation with the fund number 10872036. Therefore, the theory of multivariate numbers is still very valuable.