YES
(ignored inputs)COMMENT doi:10.1016/j.ipl.2018.04.002 [150] Example 9 submitted by: Raul Gutierrez and Salvador Lucas
Input:
   [ f(?x,?x) -> c,
     a -> b,
     b -> a ]

Make it flat:
   [ f(?x,?x) -> c,
     a -> b,
     b -> a ]
Time: 0.000 [s]

Make it Complete (R^):
   [ f(?x,?x) = f(?x_1,?x_1),
     f(?x,?x) = c,
     a = b ]
Time: 0.000 [s]

CPNF:
   [ c … c ]
Time: 0.000 [s]

Now checking all the pairs in CW...

Time to check pairs: 0.000 [s]

The TRS has Uniqueness of Normal Forms.
Total Time: 0.000 [s]

problems/797.trs: Success(UNC)
real 0.02
user 0.01
sys 0.01