(* GENERAL NOTATION USED BY THE FORMAL SYSTEM λδ ****************************)
-notation "hvbox( @ ⦃ term 46 T1 , break term 46 f ⦄ ≘ break term 46 T2 )"
+notation "hvbox( @❪ term 46 T1 , break term 46 f ❫ ≘ break term 46 T2 )"
non associative with precedence 45
for @{ 'RAt $T1 $f $T2 }.