chelovek·11 anni fa·discussThat's true. These just so happen to be ubiquitous. We can agree to call 2 a unit. To most, though, it won't be.
chelovek·11 anni fa·discuss> Instead of writing Xi, they should really write X[i]In math, x_i is i-th element in a set/list and X[i] is the ring of polynomials.