From mathcomp Require ssreflect ssrbool ssrfun bigop.
Set Implicit Arguments.
Unset Strict Implicit.
Unset Printing Implicit Defensive.
(** We will follow the development from this paper: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.43.8188&rep=rep1&type=pdf*)
Open Scope list_scope.
Module LISTTHEOREMS.
Open Scope nat_scope.

Lemma seq_peel_begin: forall (n l: nat) (LPOS: l > 0),
n :: seq (S n) (l - 1) = seq n l.