(* NOTATION FOR THE FORMAL SYSTEM λδ ****************************************)
-notation "hvbox( ⓓ { term 46 p } break term 55 T1. break term 55 T2 )"
+notation "hvbox( ⓓ[ term 46 p ] break term 55 T1. break term 55 T2 )"
non associative with precedence 55
for @{ 'SnAbbr $p $T1 $T2 }.