MAYBE
(ignored inputs)COMMENT doi:10.1007/978-3-319-63046-5_24 [118] Example 4 submitted by: Aart Middeldorp
Rewrite Rules:
   [ +(a,b) -> b,
     +(c,a) -> a,
     +(?x,?y) -> +(?y,?x),
     +(+(?x,?y),?z) -> +(?x,+(?y,?z)) ]
Apply Direct Methods...
Inner CPs:
   [ +(b,?z_1) = +(a,+(b,?z_1)),
     +(a,?z_1) = +(c,+(a,?z_1)),
     +(+(?y,?x),?z_1) = +(?x,+(?y,?z_1)),
     +(+(?x,+(?y,?z)),?z_1) = +(+(?x,?y),+(?z,?z_1)) ]
Outer CPs:
   [ b = +(b,a),
     a = +(a,c),
     +(?y,+(?x_1,?y_1)) = +(?x_1,+(?y_1,?y)) ]
Linear
(inner) Parallel CPs: (not computed)
unknown Toyama (Parallel CPs)
Direct Methods: Can't judge

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