MAYBE

Problem:
 +(0(),y) -> y
 +(s(x),y) -> s(+(x,y))
 *(x,0()) -> 0()
 *(x,s(y)) -> +(x,*(x,y))
 twice(0()) -> 0()
 twice(s(x)) -> s(s(twice(x)))
 -(x,0()) -> x
 -(s(x),s(y)) -> -(x,y)
 f(s(x)) -> f(-(*(s(s(x)),s(s(x))),+(*(s(x),s(s(x))),s(s(0())))))

Proof:
 DP Processor:
  DPs:
   +#(s(x),y) -> +#(x,y)
   *#(x,s(y)) -> *#(x,y)
   *#(x,s(y)) -> +#(x,*(x,y))
   twice#(s(x)) -> twice#(x)
   -#(s(x),s(y)) -> -#(x,y)
   f#(s(x)) -> *#(s(x),s(s(x)))
   f#(s(x)) -> +#(*(s(x),s(s(x))),s(s(0())))
   f#(s(x)) -> *#(s(s(x)),s(s(x)))
   f#(s(x)) -> -#(*(s(s(x)),s(s(x))),+(*(s(x),s(s(x))),s(s(0()))))
   f#(s(x)) -> f#(-(*(s(s(x)),s(s(x))),+(*(s(x),s(s(x))),s(s(0())))))
  TRS:
   +(0(),y) -> y
   +(s(x),y) -> s(+(x,y))
   *(x,0()) -> 0()
   *(x,s(y)) -> +(x,*(x,y))
   twice(0()) -> 0()
   twice(s(x)) -> s(s(twice(x)))
   -(x,0()) -> x
   -(s(x),s(y)) -> -(x,y)
   f(s(x)) -> f(-(*(s(s(x)),s(s(x))),+(*(s(x),s(s(x))),s(s(0())))))
  Open