MAYBE
Input TRS:
      1: R(x,a(y)) -> R(a(x),y)
      2: R(x,b()) -> L(x,a(b()))
      3: L(a(x),y) -> L(x,a(y))
      4: L(b(),x) -> R(a(b()),x)
Number of strict rules: 4
Direct POLO(bPol) ... failed.
Uncurrying ... failed.
Dependency Pairs:
     #1: #R(x,b()) -> #L(x,a(b()))
     #2: #L(a(x),y) -> #L(x,a(y))
     #3: #R(x,a(y)) -> #R(a(x),y)
     #4: #L(b(),x) -> #R(a(b()),x)
Number of SCCs: 1, DPs: 4
  SCC { #1..4 }
POLO(Sum)... POLO(max)... QLPOS... POLO(mSum)... QWPOpS(mSum)... Mat2b... failed.
Finding a loop...  failed.