YES 0.793 H-Termination proof of /home/matraf/haskell/eval_FullyBlown_Fast/empty.hs
H-Termination of the given Haskell-Program with start terms could successfully be proven:



HASKELL
  ↳ BR

mainModule Main
  ((lookup :: Ordering  ->  [(Ordering,a)]  ->  Maybe a) :: Ordering  ->  [(Ordering,a)]  ->  Maybe a)

module Main where
  import qualified Prelude



Replaced joker patterns by fresh variables and removed binding patterns.

↳ HASKELL
  ↳ BR
HASKELL
      ↳ COR

mainModule Main
  ((lookup :: Ordering  ->  [(Ordering,a)]  ->  Maybe a) :: Ordering  ->  [(Ordering,a)]  ->  Maybe a)

module Main where
  import qualified Prelude



Cond Reductions:
The following Function with conditions
undefined 
 | False
 = undefined

is transformed to
undefined  = undefined1

undefined0 True = undefined

undefined1  = undefined0 False

The following Function with conditions
lookup k [] = Nothing
lookup k ((x,y: xys)
 | k == x
 = Just y
 | otherwise
 = lookup k xys

is transformed to
lookup k [] = lookup3 k []
lookup k ((x,y: xys) = lookup2 k ((x,y: xys)

lookup0 k x y xys True = lookup k xys

lookup1 k x y xys True = Just y
lookup1 k x y xys False = lookup0 k x y xys otherwise

lookup2 k ((x,y: xys) = lookup1 k x y xys (k == x)

lookup3 k [] = Nothing
lookup3 wu wv = lookup2 wu wv



↳ HASKELL
  ↳ BR
    ↳ HASKELL
      ↳ COR
HASKELL
          ↳ Narrow

mainModule Main
  (lookup :: Ordering  ->  [(Ordering,a)]  ->  Maybe a)

module Main where
  import qualified Prelude



Haskell To QDPs


↳ HASKELL
  ↳ BR
    ↳ HASKELL
      ↳ COR
        ↳ HASKELL
          ↳ Narrow
QDP
              ↳ DependencyGraphProof

Q DP problem:
The TRS P consists of the following rules:

new_lookup(LT, :(@2(GT, ww401), ww41), ba) → new_lookup(LT, ww41, ba)
new_lookup(GT, :(@2(EQ, ww401), ww41), ba) → new_lookup(GT, ww41, ba)
new_lookup(GT, :(@2(LT, ww401), ww41), ba) → new_lookup(GT, ww41, ba)
new_lookup(EQ, :(@2(LT, ww401), ww41), ba) → new_lookup(EQ, ww41, ba)
new_lookup(LT, :(@2(EQ, ww401), ww41), ba) → new_lookup(LT, ww41, ba)
new_lookup(EQ, :(@2(GT, ww401), ww41), ba) → new_lookup(EQ, ww41, ba)

R is empty.
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
The approximation of the Dependency Graph [15,17,22] contains 3 SCCs.

↳ HASKELL
  ↳ BR
    ↳ HASKELL
      ↳ COR
        ↳ HASKELL
          ↳ Narrow
            ↳ QDP
              ↳ DependencyGraphProof
                ↳ AND
QDP
                    ↳ QDPSizeChangeProof
                  ↳ QDP
                  ↳ QDP

Q DP problem:
The TRS P consists of the following rules:

new_lookup(EQ, :(@2(LT, ww401), ww41), ba) → new_lookup(EQ, ww41, ba)
new_lookup(EQ, :(@2(GT, ww401), ww41), ba) → new_lookup(EQ, ww41, ba)

R is empty.
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By using the subterm criterion [20] together with the size-change analysis [32] we have proven that there are no infinite chains for this DP problem.

From the DPs we obtained the following set of size-change graphs:



↳ HASKELL
  ↳ BR
    ↳ HASKELL
      ↳ COR
        ↳ HASKELL
          ↳ Narrow
            ↳ QDP
              ↳ DependencyGraphProof
                ↳ AND
                  ↳ QDP
QDP
                    ↳ QDPSizeChangeProof
                  ↳ QDP

Q DP problem:
The TRS P consists of the following rules:

new_lookup(GT, :(@2(EQ, ww401), ww41), ba) → new_lookup(GT, ww41, ba)
new_lookup(GT, :(@2(LT, ww401), ww41), ba) → new_lookup(GT, ww41, ba)

R is empty.
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By using the subterm criterion [20] together with the size-change analysis [32] we have proven that there are no infinite chains for this DP problem.

From the DPs we obtained the following set of size-change graphs:



↳ HASKELL
  ↳ BR
    ↳ HASKELL
      ↳ COR
        ↳ HASKELL
          ↳ Narrow
            ↳ QDP
              ↳ DependencyGraphProof
                ↳ AND
                  ↳ QDP
                  ↳ QDP
QDP
                    ↳ QDPSizeChangeProof

Q DP problem:
The TRS P consists of the following rules:

new_lookup(LT, :(@2(GT, ww401), ww41), ba) → new_lookup(LT, ww41, ba)
new_lookup(LT, :(@2(EQ, ww401), ww41), ba) → new_lookup(LT, ww41, ba)

R is empty.
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By using the subterm criterion [20] together with the size-change analysis [32] we have proven that there are no infinite chains for this DP problem.

From the DPs we obtained the following set of size-change graphs: