fact: Definition min_nonzero_subdef (xnz ynz : nullity) (xr yr : reality) := nz_of_bool (xnz && ynz || xnz && yr && match xr with Real (Sign <=0) => true | _ => false end || ynz && match yr with Real (Sign <=0) => true | _ => false end).
imports: HB(structures) Coq(ssreflect ssrfun ssrbool) mathcomp(ssrnat eqtype choice order ssralg ssrnum ssrint) mathcomp(mathcomp_extra)