************************************************** Claim { termination = Standard , system = (VAR x1) (RULES b c -> a b b , b a -> a c b) , deadline = Just (Time -2040394096) } is false because of mirror image R' = { reverse(l) -> reverse(r) | (l -> r) in R } (VAR x1) (RULES c b -> b b a , a b -> b c a) admits a looping transport system notation: http://dfa.imn.htwk-leipzig.de/matchbox/methods/loop.pdf pivot p = [ b , b ] block alphabet Gamma = [ [ a ] , [ b ] , [ c ] ] forall g in Gamma: g p ->^* p phi(g) where phi = listToFM [ ( [ a ] , [ [ b ] , [ a ] , [ c ] , [ a ] ] ) , ( [ b ] , [ [ b ] ] ) , ( [ c ] , [ [ a ] , [ b ] ] ) ] phi ([ a ]) = [ [ b ] , [ a ] , [ c ] , [ a ] ] because of Derivation { lhs = [ a , b , b ] , rhs = [ b , b , b , a , c , a ] , hash_value = -1533806296 , strict = True , steps = [ Step { rule = 1 , position = 0 } , Step { rule = 1 , position = 2 } , Step { rule = 0 , position = 1 } ] } phi ([ b ]) = [ [ b ] ] because of Derivation { lhs = [ b ] , rhs = [ b ] , hash_value = -165547832 , strict = False , steps = [ ] } phi ([ c ]) = [ [ a ] , [ b ] ] because of Derivation { lhs = [ c , b , b ] , rhs = [ b , b , a , b ] , hash_value = -507819770 , strict = True , steps = [ Step { rule = 0 , position = 0 } ] } start s = [ a ] exponent k = 3 phi^k(s) contains s (.. p ..)^k this implies there is a loop starting at s p^k ************************************************** statistics: total atomic proof attempts number = 7, total = 5 maximal = [ Log { what = rfc match bounds (classical) , start = Time -2040400054 , end = Time -2040399549 , duration = 5 , success = False } ] successful atomic proof attempts number = 0, total = 0 maximal = [ ] failed atomic proof attempts number = 7, total = 5 maximal = [ Log { what = rfc match bounds (classical) , start = Time -2040400054 , end = Time -2040399549 , 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/tmppwwZvJ/matchbox-2007-06-01/minisat --timeout-command=/tmp/tmppwwZvJ/matchbox-2007-06-01/timeout --tmpdir=tmp --timeout=60 /tmp/tmp.l13R4qXW2h/a.srs started : Thu Jan 26 12:27:48 CET 2012 finished : Thu Jan 26 12:27:53 CET 2012 run system : Linux uc01-09 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: 5 secs