fact: Definition interval_sign (i : interval int) : option KnownSign.real := let 'Interval l u := i in (match itv_bound_signl l, itv_bound_signr u with | =0, <=0 | >=0, =0 | >=0, <=0 => None | =0, =0 => Some (KnownSign.Sign =0) | <=0, =0 | <=0, <=0 => Some (KnownSign.Sign <=0) | =0, >=0 | >=0, >=0 => Some (KnownSign.Sign >=0) | <=0, >=0 => Some >=<0 end)%snum_sign.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool) mathcomp(ssrnat eqtype choice order ssralg ssrnum ssrint) mathcomp(interval) mathcomp(mathcomp_extra boolp) signed