for @{'bigop ($b-$a) $op $nil (λ${ident j}.((λ${ident j}.true) (${ident j}+$a)))
(λ${ident j}.((λ${ident j}.$f)(${ident j}+$a)))}.
-(* notation "\big [ op , nil ]_{( term 50) a ≤ ident j < b | p } f"
+(* notation "\big [ op , nil ]_{( term 55) a ≤ ident j < b | p } f"
with precedence 80
for @{\big[$op,$nil]_{${ident j} < ($b-$a) | ((λ${ident j}.$p) (${ident j}+$a))}((λ${ident j}.$f)(${ident j}+$a))}.
*)