fact: Definition sumb (b : bool) : {b = true} + {b = false} := if b is true then left erefl else right erefl.
imports: ZArith NArith FMaps FMapAVL mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq) mathcomp(choice finfun tuple fintype ssralg bigop) CoqEAL(hrel) CoqEAL(refinements) CoqEAL(param binord binnat) CoqEAL(seqmx ) CoqEAL(ssrcomplements) mathcomp.multinomials(mpoly freeg)