YES 0.678 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
  ↳ LR

mainModule Main
  ((span :: (a  ->  Bool ->  [a ->  ([a],[a])) :: (a  ->  Bool ->  [a ->  ([a],[a]))

module Main where
  import qualified Prelude



Lambda Reductions:
The following Lambda expression
\(_,zs)→zs

is transformed to
zs0 (_,zs) = zs

The following Lambda expression
\(ys,_)→ys

is transformed to
ys0 (ys,_) = ys



↳ HASKELL
  ↳ LR
HASKELL
      ↳ BR

mainModule Main
  ((span :: (a  ->  Bool ->  [a ->  ([a],[a])) :: (a  ->  Bool ->  [a ->  ([a],[a]))

module Main where
  import qualified Prelude



Replaced joker patterns by fresh variables and removed binding patterns.
Binding Reductions:
The bind variable of the following binding Pattern
xs@(vw : vx)

is replaced by the following term
vw : vx



↳ HASKELL
  ↳ LR
    ↳ HASKELL
      ↳ BR
HASKELL
          ↳ COR

mainModule Main
  ((span :: (a  ->  Bool ->  [a ->  ([a],[a])) :: (a  ->  Bool ->  [a ->  ([a],[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
span p [] = ([],[])
span p (vw : vx)
 | p vw
 = (vw : ys,zs)
 | otherwise
 = ([],vw : vx)
where 
vu43  = span p vx
ys  = ys0 vu43
ys0 (ys,vy) = ys
zs  = zs0 vu43
zs0 (vz,zs) = zs

is transformed to
span p [] = span3 p []
span p (vw : vx) = span2 p (vw : vx)

span2 p (vw : vx) = 
span1 p vw vx (p vw)
where 
span0 p vw vx True = ([],vw : vx)
span1 p vw vx True = (vw : ys,zs)
span1 p vw vx False = span0 p vw vx otherwise
vu43  = span p vx
ys  = ys0 vu43
ys0 (ys,vy) = ys
zs  = zs0 vu43
zs0 (vz,zs) = zs

span3 p [] = ([],[])
span3 wx wy = span2 wx wy



↳ HASKELL
  ↳ LR
    ↳ HASKELL
      ↳ BR
        ↳ HASKELL
          ↳ COR
HASKELL
              ↳ LetRed

mainModule Main
  ((span :: (a  ->  Bool ->  [a ->  ([a],[a])) :: (a  ->  Bool ->  [a ->  ([a],[a]))

module Main where
  import qualified Prelude



Let/Where Reductions:
The bindings of the following Let/Where expression
span1 p vw vx (p vw)
where 
span0 p vw vx True = ([],vw : vx)
span1 p vw vx True = (vw : ys,zs)
span1 p vw vx False = span0 p vw vx otherwise
vu43  = span p vx
ys  = ys0 vu43
ys0 (ys,vy) = ys
zs  = zs0 vu43
zs0 (vz,zs) = zs

are unpacked to the following functions on top level
span2Ys wz xu = span2Ys0 wz xu (span2Vu43 wz xu)

span2Ys0 wz xu (ys,vy) = ys

span2Zs0 wz xu (vz,zs) = zs

span2Span1 wz xu p vw vx True = (vw : span2Ys wz xu,span2Zs wz xu)
span2Span1 wz xu p vw vx False = span2Span0 wz xu p vw vx otherwise

span2Zs wz xu = span2Zs0 wz xu (span2Vu43 wz xu)

span2Span0 wz xu p vw vx True = ([],vw : vx)

span2Vu43 wz xu = span wz xu



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

mainModule Main
  (span :: (a  ->  Bool ->  [a ->  ([a],[a]))

module Main where
  import qualified Prelude



Haskell To QDPs


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

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

new_span(xv3, :(xv40, xv41), ba) → new_span2Span1(xv3, xv41, xv40, ba)
new_span2Vu43(xv3, xv41, ba) → new_span(xv3, xv41, ba)
new_span2Span1(xv3, xv41, xv40, ba) → new_span2Vu43(xv3, xv41, ba)
new_span2Span1(xv3, xv41, xv40, ba) → new_span(xv3, xv41, 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: