fact: Definition consec ks t1 t2 := [&& t1 <[ks] t2 & nilp (&=ks `]t1, t2[)].
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval order) pcm(options prelude ordtype seqext slice useqord uslice)