fact: Definition ix_itv {A : eqType} (s : seq A) (i : interval A) : interval nat := let: Interval l u := i in Interval (ix_bnd s l) (ix_bnd s u).
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval order) pcm(options prelude ordtype seqext slice useqord)