% Translating A & B => B & A %query 1 * {A:o} {B:o} comb (impliesI [x:! (A & B)] andI (andER x) (andEL x)) (H A B). % Translating the result back to a natural deduction %query 1 * combdefn (MP (MP S (MP (MP S (MP K PAIR)) (MP (MP S (MP K RIGHT)) (MP (MP S K) K)))) (MP (MP S (MP K LEFT)) (MP (MP S K) K))) D. % Translating S %query 1 * combdefn S D. % Translating back the natural deduction for S %query 1 * comb (impliesI ([p:! A1 => A2 => A3] impliesI ([q:! A1 => A2] impliesI ([r:! A1] impliesE (impliesE p r) (impliesE q r))))) H.