MAYBE
Rewrite Rules:
   [ f(a,f(a,f(a,f(a,?y)))) -> f(a,f(a,f(a,g(?y,f(a,?y))))),
     f(?x,?y) -> g(?y,f(?x,?y)) ]
Apply Direct Methods...
Inner CPs:
   [ f(a,g(f(a,f(a,?y)),f(a,f(a,f(a,?y))))) = f(a,f(a,f(a,g(?y,f(a,?y))))),
     f(a,f(a,g(f(a,?y),f(a,f(a,?y))))) = f(a,f(a,f(a,g(?y,f(a,?y))))),
     f(a,f(a,f(a,g(?y_1,f(a,?y_1))))) = f(a,f(a,f(a,g(?y_1,f(a,?y_1))))),
     f(a,f(a,f(a,f(a,g(?y,f(a,?y)))))) = f(a,f(a,f(a,g(f(a,?y),f(a,f(a,?y)))))),
     f(a,f(a,f(a,f(a,f(a,g(?y,f(a,?y))))))) = f(a,f(a,f(a,g(f(a,f(a,?y)),f(a,f(a,f(a,?y))))))),
     f(a,f(a,f(a,f(a,f(a,f(a,g(?y,f(a,?y)))))))) = f(a,f(a,f(a,g(f(a,f(a,f(a,?y))),f(a,f(a,f(a,f(a,?y)))))))) ]
Outer CPs:
   [ f(a,f(a,f(a,g(?y,f(a,?y))))) = g(f(a,f(a,f(a,?y))),f(a,f(a,f(a,f(a,?y))))) ]
Left-Linear, not Right-Linear
(inner) Parallel CPs:
   [ f(a,f(a,f(a,g(?y_12,f(?x_12,?y_12))))) = f(a,f(a,f(a,g(?y_12,f(a,?y_12))))) {?y_12},
     f(a,f(a,f(a,f(a,f(a,f(a,g(?y_9,f(a,?y_9)))))))) = f(a,f(a,f(a,g(f(a,f(a,f(a,?y_9))),f(a,f(a,f(a,f(a,?y_9)))))))) {?y_9},
     f(a,f(a,g(?y_7,f(?x_7,?y_7)))) = f(a,f(a,f(a,g(?y,f(a,?y))))) {?y},
     f(a,f(a,f(a,f(a,f(a,g(?y_4,f(a,?y_4))))))) = f(a,f(a,f(a,g(f(a,f(a,?y_4)),f(a,f(a,f(a,?y_4))))))) {?y_4},
     f(a,g(f(a,f(a,?y)),f(a,f(a,f(a,?y))))) = f(a,f(a,f(a,g(?y,f(a,?y))))) {?y},
     f(a,f(a,f(a,f(a,g(?y_1,f(a,?y_1)))))) = f(a,f(a,f(a,g(f(a,?y_1),f(a,f(a,?y_1)))))) {?y_1} ]
unknown Toyama (Parallel CPs)
Direct Methods: Can't judge

Combined result: Can't judge
425.trs: Failure(unknown CR)
(1 msec.)