%% Atoms, including some sample ones for examples atom : type. %name atom P. a : atom. b : atom. c : atom. d : atom. e : atom. f : atom. %% Propositions, omitting true (tt) and false (ff) prop : type. %name prop A. => : prop -> prop -> prop. %infix right 10 =>. \/ : prop -> prop -> prop. %infix right 11 \/. /\ : prop -> prop -> prop. %infix right 12 /\. ? : atom -> prop. %prefix 14 ?. %% Some notational definitions <=> : prop -> prop -> prop = [A][B] (A => B) /\ (B => A). %infix none 9 <=>. <= : prop -> prop -> prop = [A][B] B => A. %infix left 10 <=. %% Checking some propositions _ = (? a => ? a) : prop. _ = (? a => ? b => ? a) : prop.