**************************************************
Claim
{ termination = Standard
, system = (VAR x1)
(RULES a -> ,
a a b -> c a ,
a c -> c b a a)
, deadline = Just
(Time
-2040336310)
}
is false because of
mirror image
R' = { reverse(l) -> reverse(r) | (l -> r) in R }
(VAR x1)
(RULES a -> ,
b a a -> a c ,
c a -> a a b c)
admits a looping transport system
notation: http://dfa.imn.htwk-leipzig.de/matchbox/methods/loop.pdf
pivot p = [ a , a ]
block alphabet Gamma = [ [ a , a ] , [ a , c ] , [ b , c ] , [ c ]
, [ c , b ]
]
forall g in Gamma: g p ->^* p phi(g) where
phi = listToFM
[ ( [ a , a ] , [ ] )
, ( [ a , c ] , [ [ a , a ] , [ c , b ] , [ c ] ] )
, ( [ b , c ] , [ [ b , c ] , [ c , b ] , [ c ] ] )
, ( [ c ] , [ [ a , c ] , [ b , c ] ] )
, ( [ c , b ] , [ [ b , c ] , [ c ] ] )
]
phi ([ a , a ]) = [ ]
because of Derivation
{ lhs = [ a , a , a , a ] , rhs = [ a , a ]
, hash_value = -213036735 , strict = True
, steps = [ Step
{ rule = 0 , position = 0 }
, Step
{ rule = 0 , position = 0 }
]
}
phi ([ a , c ]) = [ [ a , a ] , [ c , b ] , [ c ] ]
because of Derivation
{ lhs = [ a , c , a , a ] , rhs = [ a , a , a , a , c , b , c ]
, hash_value = -1769603782 , strict = True
, steps = [ Step
{ rule = 2 , position = 1 }
, Step
{ rule = 2 , position = 4 }
, Step
{ rule = 1 , position = 3 }
]
}
phi ([ b , c ]) = [ [ b , c ] , [ c , b ] , [ c ] ]
because of Derivation
{ lhs = [ b , c , a , a ] , rhs = [ a , a , b , c , c , b , c ]
, hash_value = -26344444 , strict = True
, steps = [ Step
{ rule = 2 , position = 1 }
, Step
{ rule = 2 , position = 4 }
, Step
{ rule = 1 , position = 0 }
, Step
{ rule = 0 , position = 0 }
, Step
{ rule = 1 , position = 1 }
, Step
{ rule = 2 , position = 0 }
]
}
phi ([ c ]) = [ [ a , c ] , [ b , c ] ]
because of Derivation
{ lhs = [ c , a , a ] , rhs = [ a , a , a , c , b , c ]
, hash_value = 1058579968 , strict = True
, steps = [ Step
{ rule = 2 , position = 0 }
, Step
{ rule = 2 , position = 3 }
, Step
{ rule = 1 , position = 2 }
]
}
phi ([ c , b ]) = [ [ b , c ] , [ c ] ]
because of Derivation
{ lhs = [ c , b , a , a ] , rhs = [ a , a , b , c , c ]
, hash_value = 1142084671 , strict = True
, steps = [ Step
{ rule = 1 , position = 1 }
, Step
{ rule = 2 , position = 0 }
]
}
start s = [ a , c ]
exponent k = 6
phi^k(s) contains s (.. p ..)^k
this implies there is a loop starting at s p^k
**************************************************
statistics:
total atomic proof attempts
number = 8, total = 5
maximal = [ Log
{ what = rfc match bounds (classical)
, start = Time
-2040342262
, end = Time
-2040341758
, duration = 5 , success = False
}
]
successful atomic proof attempts
number = 1, total = 0
maximal = [ Log
{ what = simplex
, start = Time
-2040342262
, end = Time
-2040342262
, duration = 0 , success = True
}
]
failed atomic proof attempts
number = 7, total = 5
maximal = [ Log
{ what = rfc match bounds (classical)
, start = Time
-2040342262
, end = Time
-2040341758
, duration = 5 , success = False
}
]
**************************************************
matchbox general information (including details on proof methods):
http://dfa.imn.htwk-leipzig.de/matchbox/
this matchbox implementation uses the SAT solver
MiniSat by Niklas Een and Niklas Sörensson
http://www.cs.chalmers.se/Cs/Research/FormalMethods/MiniSat/
matchbox process information
arguments : --solver=/tmp/tmpHtlhcd/matchbox-2007-06-01/minisat --timeout-command=/tmp/tmpHtlhcd/matchbox-2007-06-01/timeout --tmpdir=tmp --timeout=60 /tmp/tmp.jIvpTUCYgm/a.srs
started : Thu Jan 26 12:37:08 CET 2012
finished : Thu Jan 26 12:37:14 CET 2012
run system : Linux uc01-02 2.6.32-5-amd64 #1 SMP Tue Jun 14 09:42:28 UTC 2011 x86_64
release date : Fri Jun 1 17:36:44 CEST 2007
build date : Fri Jun 1 17:36:44 CEST 2007
build system : Linux dfa 2.6.8-2-k7 #1 Tue Aug 16 14:00:15 UTC 2005 i686 GNU/Linux
used clock time: 6 secs