4.3.out x = x ]]> y) => y) = x ]]> y = x => (x => y) ]]> def)") ]]> (x => y) = x -> y ]]> 0 ]]> 0 = ~ x ]]> x = 1 ]]> (y => x) = 1 ]]> (y => z) = y => (x => z) ]]> y) ^ (z => y) = (x v z) => y ]]> B) ^ B != B ]]> B != A => B ]]> (B => C) != B => (A -> C) ]]> B) != A ]]> 0 = x ]]> (y => (x => z)) = y => (x -> z) ]]> (y => 0) = y => ~ x ]]> x = 1 ^ (y => x) ]]> ~ y = y => x ]]> y = ~ y => x ]]> (~ x => y) = 1 ]]> (~ x => y)) = x ]]> y) = x ]]> x) = x ]]> y) ^ y = y ]]> x = y => x ]]> y = x => y ]]> (x => (y => z)) = y => (x -> z) ]]> (y => z) = y => (x -> z) ]]>