addNats :: Int -> Int addNats 0 = 0 -- addNats.1 addNats n = n + addNats (n - 1) -- addNats.2 natList :: Int -> [Int] natList 0 =  -- natList.1 natList n = n : natList (n - 1) -- natList.2 sumList :: [Int] -> Int sumList  = 0 -- sumList.1 sumList (x:xs) = x + sumList xs -- sumList.2
Show by equational reasoning and induction that, for every natural number n, we have
addNats n = sumList (natList (n))
Do not forget to provide justifications for each proof step.
Last modified: Tue Oct 30 09:29:45 EST 2001