fact: Definition normr0_eq0 V (x : V) : `|x| = 0 -> x = 0 := @normr0_eq0 R V x.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)