MAYBE
Input TRS:
      1: diff(x,y) -> cond1(equal(x,y),x,y)
      2: cond1(true(),x,y) -> 0()
      3: cond1(false(),x,y) -> cond2(gt(x,y),x,y)
      4: cond2(true(),x,y) -> s(diff(x,s(y)))
      5: cond2(false(),x,y) -> s(diff(s(x),y))
      6: gt(0(),v) -> false()
      7: gt(s(u),0()) -> true()
      8: gt(s(u),s(v)) -> gt(u,v)
      9: equal(0(),0()) -> true()
      10: equal(s(x),0()) -> false()
      11: equal(0(),s(y)) -> false()
      12: equal(s(x),s(y)) -> equal(x,y)
Number of strict rules: 12
Direct POLO(bPol) ... failed.
Uncurrying ... failed.
Dependency Pairs:
     #1: #equal(s(x),s(y)) -> #equal(x,y)
     #2: #cond2(false(),x,y) -> #diff(s(x),y)
     #3: #cond1(false(),x,y) -> #cond2(gt(x,y),x,y)
     #4: #cond1(false(),x,y) -> #gt(x,y)
     #5: #diff(x,y) -> #cond1(equal(x,y),x,y)
     #6: #diff(x,y) -> #equal(x,y)
     #7: #gt(s(u),s(v)) -> #gt(u,v)
     #8: #cond2(true(),x,y) -> #diff(x,s(y))
Number of SCCs: 3, DPs: 6
  SCC { #7 }
POLO(Sum)... succeeded.
      cond2	w: 0
      diff	w: 0
      s 	w: x1 + 1
      #cond1	w: 0
      gt	w: 0
      #equal	w: 0
      false	w: 0
      true	w: 0
      cond1	w: 0
      0 	w: 0
      #gt	w: x1
      #diff	w: 0
      equal	w: 0
      #cond2	w: 0
    USABLE RULES: { }
    Removed DPs: #7
Number of SCCs: 2, DPs: 5
  SCC { #1 }
POLO(Sum)... succeeded.
      cond2	w: 0
      diff	w: 0
      s 	w: x1 + 1
      #cond1	w: 0
      gt	w: 0
      #equal	w: x2
      false	w: 0
      true	w: 0
      cond1	w: 0
      0 	w: 0
      #gt	w: 0
      #diff	w: 0
      equal	w: 0
      #cond2	w: 0
    USABLE RULES: { }
    Removed DPs: #1
Number of SCCs: 1, DPs: 4
  SCC { #2 #3 #5 #8 }
POLO(Sum)... POLO(max)... QLPOS... POLO(mSum)... QWPOpS(mSum)... Mat2b... failed.
Finding a loop...  failed.