fact: Definition sep_interval x1 x2 := let w := (x1 + x2) / 2 in Interval (IF x2 <= w then x2 - 1 else w) (IF x2 >= w then x2 + 1 else w).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype tuple path fingraph bigop order ssralg) mathcomp(ssrnum ssrint div intdiv) fourcolor(hypermap geometry coloring grid matte) fourcolor(real realplane) Coq(Setoid Morphisms) fourcolor(realsyntax realprop)