MAYBE
(ignored inputs)COMMENT submitted by: Johannes Waldmann secret problem 2019 category: SRS
Rewrite Rules:
   [ b(?x) -> c(d(?x)),
     d(?x) -> c(b(?x)),
     c(?x) -> b(d(?x)),
     b(?x) -> c(d(?x)),
     a(?x) -> a(b(?x)),
     a(?x) -> b(c(?x)) ]
Apply Direct Methods...
Inner CPs:
   [  ]
Outer CPs:
   [ c(d(?x)) = c(d(?x)),
     a(b(?x_4)) = b(c(?x_4)) ]
Linear
(inner) Parallel CPs: (not computed)
unknown Toyama (Parallel CPs)
Direct Methods: Can't judge

Combined result: Can't judge
1132.trs: Failure(unknown CR)
(0 msec.)