- LT -> let (found,lt,gt) = splitMember x l in (found,lt,join y gt r)
- GT -> let (found,lt,gt) = splitMember x r in (found,join y l lt,gt)
- EQ -> (True,l,r)
+ LT -> let (lt,found,gt) = splitMember x l in (lt,found,join y gt r)
+ GT -> let (lt,found,gt) = splitMember x r in (join y l lt,found,gt)
+ EQ -> (l,True,r)