End ReductionHesselink.
Section Palindrome.
Variable Gamma' : finType.
Inductive Gamma := emb (x : Gamma') | StartG.
Global Instance eq_dec_gamma : eq_dec Gamma.
Definition emb_string := map emb.
Definition palin_G : cfg Gamma :=
(StartG, (StartG, []) ::
flat_map (fun g => [ (StartG, [emb g]);  (StartG, [emb g; StartG; emb g]) ]) (elem Gamma')).

Lemma G_char (x : list Gamma') :
x = rev x <-> L palin_G (emb_string x).