 | suffix list p to each element of set *)
(<.>) :: Ord a => [a] -> S.Set [a]  -> S.Set [a]
(<.>) pos set = S.map (\pos' -> pos ++ pos' ) set 

(<.>) :: Ord a => [a] -> S.Set [a]  -> S.Set [a]
(<.>) pos set = S.map (\pos' -> pos ++ pos' ) set
(<.>) pos set = S.map (\pos' -> pos ++ pos' ) set