refl
(ismember (set-unionm n)) x) == (ismember (union m n) x)
union-pair' m n x with ismember m x | ismember n x | ismember (set-union| false | false | false = trans {x = ismember
上执行联合操作,lists.The逻辑是correct.But卡在一个错误上的,这是:我的代码是: ((not (member (first L2) L1)) ;check if first member of l2 is in l1 or not (set-union L1 (rest L2)))
)) ;if second co