(*
(* other notations **********************************************************)
-notation "hvbox(\langle term 19 a, break term 19 b\rangle)"
-with precedence 90 for @{ 'pair $a $b}.
-
notation "hvbox(x break \times y)" with precedence 70
for @{ 'product $x $y}.
(*
notation < "s \sup (-1) x" non associative with precedence 90 for @{ 'invert_appl $s $x}.
-notation "| term 19 C |" with precedence 70 for @{ 'card $C }.
-
notation "\naturals" non associative with precedence 90 for @{'N}.
notation "\rationals" non associative with precedence 90 for @{'Q}.
notation "\reals" non associative with precedence 90 for @{'R}.