End string_rewriting.
Definition SR_fin (S: sigT (fun (sig:finType) => (prod (prod (srs sig) (list sig)) (list sig)))) :=
match (projT2 S) with
|(rules,x,y) => rewt' rules x y
end.
Section Fix_TM.
Variable sig : finType.
Variable T : (sTM sig).
Definition conf :Type := mconfig sig (states T).
Instance eq_dec_states : eq_dec (states T).

Lemma symb_count_one s:
count (map (fun s0 : FinType (EqType rsig') => symb s0)
(elem (FinType (EqType rsig')))) (symb s) = 1.