MAYBE 1.619 H-Termination proof of /home/matraf/haskell/eval_FullyBlown_Fast/empty.hs
H-Termination of the given Haskell-Program with start terms could not be shown:



HASKELL
  ↳ LR

mainModule Main
  ((mapM :: (b  ->  [a])  ->  [b ->  [[a]]) :: (b  ->  [a])  ->  [b ->  [[a]])

module Main where
  import qualified Prelude



Lambda Reductions:
The following Lambda expression
\xsreturn (x : xs)

is transformed to
sequence0 x xs = return (x : xs)

The following Lambda expression
\xsequence cs >>= sequence0 x

is transformed to
sequence1 cs x = sequence cs >>= sequence0 x



↳ HASKELL
  ↳ LR
HASKELL
      ↳ BR

mainModule Main
  ((mapM :: (b  ->  [a])  ->  [b ->  [[a]]) :: (b  ->  [a])  ->  [b ->  [[a]])

module Main where
  import qualified Prelude



Replaced joker patterns by fresh variables and removed binding patterns.

↳ HASKELL
  ↳ LR
    ↳ HASKELL
      ↳ BR
HASKELL
          ↳ COR

mainModule Main
  ((mapM :: (a  ->  [b])  ->  [a ->  [[b]]) :: (a  ->  [b])  ->  [a ->  [[b]])

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



↳ HASKELL
  ↳ LR
    ↳ HASKELL
      ↳ BR
        ↳ HASKELL
          ↳ COR
HASKELL
              ↳ Narrow
              ↳ Narrow

mainModule Main
  (mapM :: (b  ->  [a])  ->  [b ->  [[a]])

module Main where
  import qualified Prelude



Haskell To QDPs


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

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

new_psPs(:(vx80, vx81), vx6, ba) → new_psPs(vx81, vx6, 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
  ↳ LR
    ↳ HASKELL
      ↳ BR
        ↳ HASKELL
          ↳ COR
            ↳ HASKELL
              ↳ Narrow
                ↳ AND
                  ↳ QDP
QDP
                    ↳ QDPSizeChangeProof
                  ↳ QDP
              ↳ Narrow

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

new_gtGtEs(:(vx710, vx711), vx50, ba) → new_gtGtEs(vx711, vx50, 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
  ↳ LR
    ↳ HASKELL
      ↳ BR
        ↳ HASKELL
          ↳ COR
            ↳ HASKELL
              ↳ Narrow
                ↳ AND
                  ↳ QDP
                  ↳ QDP
QDP
                    ↳ UsableRulesProof
              ↳ Narrow

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

new_psPs0(vx3, vx41, ba, bb) → new_sequence(vx3, vx41, ba, bb)
new_sequence(vx3, :(vx40, vx41), ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)
new_gtGtEs0(vx3, vx41, ba, bb) → new_psPs0(vx3, vx41, ba, bb)
new_gtGtEs0(vx3, vx41, ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)

The TRS R consists of the following rules:

new_gtGtEs1(:(vx50, vx51), vx3, vx41, ba, bb) → new_psPs5(vx3, vx41, vx50, new_gtGtEs1(vx51, vx3, vx41, ba, bb), ba, bb)
new_psPs4([], vx6, ba) → vx6
new_psPs5(vx3, vx41, vx50, vx6, ba, bb) → new_psPs2(new_sequence0(vx3, vx41, ba, bb), vx50, vx6, ba)
new_psPs2([], vx50, vx6, ba) → new_psPs1(vx6, ba)
new_gtGtEs1([], vx3, vx41, ba, bb) → []
new_psPs1(vx6, ba) → vx6
new_gtGtEs2([], vx50, ba) → []
new_psPs2(:(vx70, vx71), vx50, vx6, ba) → new_psPs3(vx50, vx70, new_psPs1(new_gtGtEs2(vx71, vx50, ba), ba), vx6, ba)
new_gtGtEs2(:(vx710, vx711), vx50, ba) → new_psPs4(:(:(vx50, vx710), []), new_gtGtEs2(vx711, vx50, ba), ba)
new_psPs3(vx50, vx70, vx8, vx6, ba) → :(:(vx50, vx70), new_psPs4(vx8, vx6, ba))
new_psPs4(:(vx80, vx81), vx6, ba) → :(vx80, new_psPs4(vx81, vx6, ba))

The set Q consists of the following terms:

new_psPs1(x0, x1)
new_psPs2([], x0, x1, x2)
new_psPs4([], x0, x1)
new_gtGtEs2(:(x0, x1), x2, x3)
new_psPs3(x0, x1, x2, x3, x4)
new_gtGtEs1(:(x0, x1), x2, x3, x4, x5)
new_gtGtEs2([], x0, x1)
new_gtGtEs1([], x0, x1, x2, x3)
new_psPs4(:(x0, x1), x2, x3)
new_psPs5(x0, x1, x2, x3, x4, x5)
new_psPs2(:(x0, x1), x2, x3, x4)

We have to consider all minimal (P,Q,R)-chains.
As all Q-normal forms are R-normal forms we are in the innermost case. Hence, by the usable rules processor [15] we can delete all non-usable rules [17] from R.

↳ HASKELL
  ↳ LR
    ↳ HASKELL
      ↳ BR
        ↳ HASKELL
          ↳ COR
            ↳ HASKELL
              ↳ Narrow
                ↳ AND
                  ↳ QDP
                  ↳ QDP
                  ↳ QDP
                    ↳ UsableRulesProof
QDP
                        ↳ QReductionProof
              ↳ Narrow

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

new_psPs0(vx3, vx41, ba, bb) → new_sequence(vx3, vx41, ba, bb)
new_sequence(vx3, :(vx40, vx41), ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)
new_gtGtEs0(vx3, vx41, ba, bb) → new_psPs0(vx3, vx41, ba, bb)
new_gtGtEs0(vx3, vx41, ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)

R is empty.
The set Q consists of the following terms:

new_psPs1(x0, x1)
new_psPs2([], x0, x1, x2)
new_psPs4([], x0, x1)
new_gtGtEs2(:(x0, x1), x2, x3)
new_psPs3(x0, x1, x2, x3, x4)
new_gtGtEs1(:(x0, x1), x2, x3, x4, x5)
new_gtGtEs2([], x0, x1)
new_gtGtEs1([], x0, x1, x2, x3)
new_psPs4(:(x0, x1), x2, x3)
new_psPs5(x0, x1, x2, x3, x4, x5)
new_psPs2(:(x0, x1), x2, x3, x4)

We have to consider all minimal (P,Q,R)-chains.
We deleted the following terms from Q as each root-symbol of these terms does neither occur in P nor in R.

new_psPs1(x0, x1)
new_psPs2([], x0, x1, x2)
new_psPs4([], x0, x1)
new_gtGtEs2(:(x0, x1), x2, x3)
new_psPs3(x0, x1, x2, x3, x4)
new_gtGtEs1(:(x0, x1), x2, x3, x4, x5)
new_gtGtEs2([], x0, x1)
new_gtGtEs1([], x0, x1, x2, x3)
new_psPs4(:(x0, x1), x2, x3)
new_psPs5(x0, x1, x2, x3, x4, x5)
new_psPs2(:(x0, x1), x2, x3, x4)



↳ HASKELL
  ↳ LR
    ↳ HASKELL
      ↳ BR
        ↳ HASKELL
          ↳ COR
            ↳ HASKELL
              ↳ Narrow
                ↳ AND
                  ↳ QDP
                  ↳ QDP
                  ↳ QDP
                    ↳ UsableRulesProof
                      ↳ QDP
                        ↳ QReductionProof
QDP
                            ↳ UsableRulesReductionPairsProof
              ↳ Narrow

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

new_psPs0(vx3, vx41, ba, bb) → new_sequence(vx3, vx41, ba, bb)
new_sequence(vx3, :(vx40, vx41), ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)
new_gtGtEs0(vx3, vx41, ba, bb) → new_psPs0(vx3, vx41, ba, bb)
new_gtGtEs0(vx3, vx41, ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)

R is empty.
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
By using the usable rules with reduction pair processor [15] with a polynomial ordering [25], all dependency pairs and the corresponding usable rules [17] can be oriented non-strictly. All non-usable rules are removed, and those dependency pairs and usable rules that have been oriented strictly or contain non-usable symbols in their left-hand side are removed as well.

The following dependency pairs can be deleted:

new_sequence(vx3, :(vx40, vx41), ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)
No rules are removed from R.

Used ordering: POLO with Polynomial interpretation [25]:

POL(:(x1, x2)) = 2 + x1 + 2·x2   
POL(new_gtGtEs0(x1, x2, x3, x4)) = 2 + x1 + 2·x2 + x3 + x4   
POL(new_psPs0(x1, x2, x3, x4)) = 2 + x1 + x2 + x3 + x4   
POL(new_sequence(x1, x2, x3, x4)) = 2 + x1 + x2 + x3 + x4   



↳ HASKELL
  ↳ LR
    ↳ HASKELL
      ↳ BR
        ↳ HASKELL
          ↳ COR
            ↳ HASKELL
              ↳ Narrow
                ↳ AND
                  ↳ QDP
                  ↳ QDP
                  ↳ QDP
                    ↳ UsableRulesProof
                      ↳ QDP
                        ↳ QReductionProof
                          ↳ QDP
                            ↳ UsableRulesReductionPairsProof
QDP
                                ↳ DependencyGraphProof
              ↳ Narrow

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

new_psPs0(vx3, vx41, ba, bb) → new_sequence(vx3, vx41, ba, bb)
new_gtGtEs0(vx3, vx41, ba, bb) → new_psPs0(vx3, vx41, ba, bb)
new_gtGtEs0(vx3, vx41, ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)

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 1 SCC with 2 less nodes.

↳ HASKELL
  ↳ LR
    ↳ HASKELL
      ↳ BR
        ↳ HASKELL
          ↳ COR
            ↳ HASKELL
              ↳ Narrow
                ↳ AND
                  ↳ QDP
                  ↳ QDP
                  ↳ QDP
                    ↳ UsableRulesProof
                      ↳ QDP
                        ↳ QReductionProof
                          ↳ QDP
                            ↳ UsableRulesReductionPairsProof
                              ↳ QDP
                                ↳ DependencyGraphProof
QDP
                                    ↳ NonTerminationProof
              ↳ Narrow

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

new_gtGtEs0(vx3, vx41, ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)

R is empty.
Q is empty.
We have to consider all minimal (P,Q,R)-chains.
We used the non-termination processor [17] to show that the DP problem is infinite.
Found a loop by semiunifying a rule from P directly.

The TRS P consists of the following rules:

new_gtGtEs0(vx3, vx41, ba, bb) → new_gtGtEs0(vx3, vx41, ba, bb)

The TRS R consists of the following rules:none


s = new_gtGtEs0(vx3, vx41, ba, bb) evaluates to t =new_gtGtEs0(vx3, vx41, ba, bb)

Thus s starts an infinite chain as s semiunifies with t with the following substitutions:




Rewriting sequence

The DP semiunifies directly so there is only one rewrite step from new_gtGtEs0(vx3, vx41, ba, bb) to new_gtGtEs0(vx3, vx41, ba, bb).




Haskell To QDPs