definition fun_of_seq: ∀O:Type.sequence O → nat → O ≝
λO.λx:sequence O.match x with [ mk_seq f ⇒ f ].
-coercion cic:/matita/dama/sequence/fun_of_seq.con 1.
+coercion fun_of_seq 1.
notation < "hvbox((\lfloor term 19 p \rfloor) \sub ident i)" with precedence 90
for @{ 'sequence (\lambda ${ident i} : $t . $p)}.
notation "a \sub i" left associative with precedence 90
for @{ 'sequence_appl $a $i }.
-interpretation "sequence" 'sequence \eta.x = (mk_seq _ x).
-interpretation "sequence element" 'sequence_appl s i = (fun_of_seq _ s i).
+interpretation "sequence" 'sequence \eta.x = (mk_seq ? x).
+interpretation "sequence element" 'sequence_appl s i = (fun_of_seq ? s i).