fact: Definition sqrtc (x : R[i]) : R[i] := let: a +i* b := x in let sgr1 b := if b == 0 then 1 else sgr b in let r := sqrtr (a^+2 + b^+2) in (sqrtr ((r + a)/2%:R)) +i* (sgr1 b * sqrtr ((r - a)/2%:R)).
imports: HB(structures) mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg ssrint div ssrnum rat poly closed_field) mathcomp(polyrcf matrix mxalgebra tuple mxpoly zmodp binomial realalg) mathcomp(mxpoly)