subOneLists :: [a] -> [[a]]
subOneLists ls = let  helper :: [a] -> [a] -> [[a]] -> [[a]]
                      helper _ [] ss = ss
                      helper ps (x:xs) ss = helper ps' xs ss'
                        where ps' = ps ++ [x]
                              ss' = ss ++ [ps ++ xs]
                 in helper [] ls []

λ> subOneLists [1, 2, 3, 4]
[[2,3,4],[1,3,4],[1,2,4],[1,2,3]]

subOneLists :: [a] -> [[a]]
subOneLists [] = []
subOneLists (x:xs) = xs : map (x :) (subOneLists xs)