NO
af/ONE-SORTED/707.trs
Input rules:
   [ c -> a,
     f(f(c)) -> c,
     f(c) -> a ]
Sorts having no ground terms: 
Rules applicable to ground terms:
   [ c -> a,
     f(f(c)) -> c,
     f(c) -> a ]
Constructor pattern: [a,f(?x_1)]
Defined pattern: [c]
Constructor subsystem:
   [ ]
Modified Constructor subsystem:
   [ ]
candidate for c:
   [ c -> a ]
Find a quasi-ordering ...
order successfully found
Precedence:
 c : Mul;
 a : Mul;
 f : Mul;
Rules:
   [ c -> a ]
Conjectures:
   [ f(f(c)) = c,
     f(c) = a ]
STEP 0
ES:
   [ f(f(c)) = c,
     f(c) = a ]
HS:
   [ ]
ES0:
   [ f(f(a)) = a,
     f(a) = a ]
HS0:
   [ ]
ES1:
   [ f(f(a)) = a,
     f(a) = a ]
HS1:
   [ ]
No equation to expand
check Non-Ground-Confluence...
ground constructor terms for instantiation: {a,f(a)}
ground terms for instantiation: {a:o,f(a):o}
obtain 10 rules by 3 steps unfolding
obtain 20 candidates for checking non-joinability
check by TCAP-Approximation (success)
Witness for Non-Confluence: <f(a) <- f(f(f(f(f(f(c)))))) -> a>
: Success(not GCR)
(3 msec.)
0.02