?& is logical and: yes when every test is yes.

?&((gth 5 3) (lth 2 9)) is %.y.

irregular forms:

&(a b) is ?&(a b)

%: calls a gate with several arguments, gathering them into one sample.

%:(add 2 3) is 5.

irregular forms:

(gate a b c) is %:(gate a b c)

gth asks whether the first atom is strictly greater than the second.

(gth 5 3) is %.y.

lth asks whether the first atom is strictly less than the second.

(lth 5 3) is %.n.