**************************************************
Claim
{ termination = Standard
, system = (VAR x1)
(RULES a -> ,
a -> b b ,
b b b c -> c c a a)
, deadline = Just
(Time
-2040305494)
}
is false because of
mirror image
R' = { reverse(l) -> reverse(r) | (l -> r) in R }
(VAR x1)
(RULES a -> ,
a -> b b ,
c b b b -> a a c 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 , c ] , [ c ] , [ c , a ]
, [ c , b ]
]
forall g in Gamma: g p ->^* p phi(g) where
phi = listToFM
[ ( [ a ] , [ [ a ] ] ) , ( [ a , c ] , [ [ a , c ] , [ c , b ] ] )
, ( [ c ] , [ [ c ] , [ c , b ] ] )
, ( [ c , a ] , [ [ c ] , [ c , b ] , [ a ] ] )
, ( [ c , b ] , [ [ c ] , [ c , a ] ] )
]
phi ([ a ]) = [ [ a ] ]
because of Derivation
{ lhs = [ a ] , rhs = [ a ] , hash_value = -165557840
, strict = False , steps = [ ]
}
phi ([ a , c ]) = [ [ a , c ] , [ c , b ] ]
because of Derivation
{ lhs = [ a , c , a , a ] , rhs = [ a , a , a , c , c , b ]
, hash_value = -1720611984 , strict = True
, steps = [ Step
{ rule = 1 , position = 2 }
, Step
{ rule = 1 , position = 4 }
, Step
{ rule = 2 , position = 1 }
]
}
phi ([ c ]) = [ [ c ] , [ c , b ] ]
because of Derivation
{ lhs = [ c , a , a ] , rhs = [ a , a , c , c , b ]
, hash_value = -2122618054 , strict = True
, steps = [ Step
{ rule = 1 , position = 1 }
, Step
{ rule = 1 , position = 3 }
, Step
{ rule = 2 , position = 0 }
]
}
phi ([ c , a ]) = [ [ c ] , [ c , b ] , [ a ] ]
because of Derivation
{ lhs = [ c , a , a , a ] , rhs = [ a , a , c , c , b , a ]
, hash_value = -248959446 , strict = True
, steps = [ Step
{ rule = 1 , position = 1 }
, Step
{ rule = 1 , position = 3 }
, Step
{ rule = 2 , position = 0 }
]
}
phi ([ c , b ]) = [ [ c ] , [ c , a ] ]
because of Derivation
{ lhs = [ c , b , a , a ] , rhs = [ a , a , c , c , a ]
, hash_value = 1914246872 , strict = True
, steps = [ Step
{ rule = 1 , position = 2 }
, Step
{ rule = 2 , position = 0 }
]
}
start s = [ a , c ]
exponent k = 8
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
-2040311424
, end = Time
-2040310920
, duration = 5 , success = False
}
]
successful atomic proof attempts
number = 1, total = 0
maximal = [ Log
{ what = simplex
, start = Time
-2040311424
, end = Time
-2040311424
, duration = 0 , success = True
}
]
failed atomic proof attempts
number = 7, total = 5
maximal = [ Log
{ what = rfc match bounds (classical)
, start = Time
-2040311424
, end = Time
-2040310920
, 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/tmpLPb48N/matchbox-2007-06-01/minisat --timeout-command=/tmp/tmpLPb48N/matchbox-2007-06-01/timeout --tmpdir=tmp --timeout=60 /tmp/tmp.cimwV4C2QF/a.srs
started : Thu Jan 26 12:42:08 CET 2012
finished : Thu Jan 26 12:42:14 CET 2012
run system : Linux uc01-03 2.6.32-5-amd64 #1 SMP Mon Mar 7 21:35:22 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