YES

Problem:
 a(x1) -> x1
 a(b(c(x1))) -> c(c(b(b(a(x1)))))
 b(x1) -> a(x1)

Proof:
 String Reversal Processor:
  a(x1) -> x1
  c(b(a(x1))) -> a(b(b(c(c(x1)))))
  b(x1) -> a(x1)
  DP Processor:
   DPs:
    c#(b(a(x1))) -> c#(x1)
    c#(b(a(x1))) -> c#(c(x1))
    c#(b(a(x1))) -> b#(c(c(x1)))
    c#(b(a(x1))) -> b#(b(c(c(x1))))
    c#(b(a(x1))) -> a#(b(b(c(c(x1)))))
    b#(x1) -> a#(x1)
   TRS:
    a(x1) -> x1
    c(b(a(x1))) -> a(b(b(c(c(x1)))))
    b(x1) -> a(x1)
   TDG Processor:
    DPs:
     c#(b(a(x1))) -> c#(x1)
     c#(b(a(x1))) -> c#(c(x1))
     c#(b(a(x1))) -> b#(c(c(x1)))
     c#(b(a(x1))) -> b#(b(c(c(x1))))
     c#(b(a(x1))) -> a#(b(b(c(c(x1)))))
     b#(x1) -> a#(x1)
    TRS:
     a(x1) -> x1
     c(b(a(x1))) -> a(b(b(c(c(x1)))))
     b(x1) -> a(x1)
    graph:
     c#(b(a(x1))) -> b#(b(c(c(x1)))) -> b#(x1) -> a#(x1)
     c#(b(a(x1))) -> b#(c(c(x1))) -> b#(x1) -> a#(x1)
     c#(b(a(x1))) -> c#(c(x1)) -> c#(b(a(x1))) -> a#(b(b(c(c(x1)))))
     c#(b(a(x1))) -> c#(c(x1)) -> c#(b(a(x1))) -> b#(b(c(c(x1))))
     c#(b(a(x1))) -> c#(c(x1)) -> c#(b(a(x1))) -> b#(c(c(x1)))
     c#(b(a(x1))) -> c#(c(x1)) -> c#(b(a(x1))) -> c#(c(x1))
     c#(b(a(x1))) -> c#(c(x1)) -> c#(b(a(x1))) -> c#(x1)
     c#(b(a(x1))) -> c#(x1) -> c#(b(a(x1))) -> a#(b(b(c(c(x1)))))
     c#(b(a(x1))) -> c#(x1) -> c#(b(a(x1))) -> b#(b(c(c(x1))))
     c#(b(a(x1))) -> c#(x1) -> c#(b(a(x1))) -> b#(c(c(x1)))
     c#(b(a(x1))) -> c#(x1) -> c#(b(a(x1))) -> c#(c(x1))
     c#(b(a(x1))) -> c#(x1) -> c#(b(a(x1))) -> c#(x1)
    SCC Processor:
     #sccs: 1
     #rules: 2
     #arcs: 12/36
     DPs:
      c#(b(a(x1))) -> c#(c(x1))
      c#(b(a(x1))) -> c#(x1)
     TRS:
      a(x1) -> x1
      c(b(a(x1))) -> a(b(b(c(c(x1)))))
      b(x1) -> a(x1)
     Arctic Interpretation Processor:
      dimension: 2
      usable rules:
       a(x1) -> x1
       c(b(a(x1))) -> a(b(b(c(c(x1)))))
       b(x1) -> a(x1)
      interpretation:
       [c#](x0) = [-& 0 ]x0 + [0],
       
                 [0 0]     [0]
       [c](x0) = [0 0]x0 + [0],
       
                 [0  0 ]     [0]
       [a](x0) = [-& 0 ]x0 + [2],
       
                 [0 0]     [1]
       [b](x0) = [2 0]x0 + [3]
      orientation:
       c#(b(a(x1))) = [2 2]x1 + [3] >= [0 0]x1 + [0] = c#(c(x1))
       
       c#(b(a(x1))) = [2 2]x1 + [3] >= [-& 0 ]x1 + [0] = c#(x1)
       
               [0  0 ]     [0]           
       a(x1) = [-& 0 ]x1 + [2] >= x1 = x1
       
                     [2 2]     [3]    [2 2]     [3]                    
       c(b(a(x1))) = [2 2]x1 + [3] >= [2 2]x1 + [3] = a(b(b(c(c(x1)))))
       
               [0 0]     [1]    [0  0 ]     [0]        
       b(x1) = [2 0]x1 + [3] >= [-& 0 ]x1 + [2] = a(x1)
      problem:
       DPs:
        
       TRS:
        a(x1) -> x1
        c(b(a(x1))) -> a(b(b(c(c(x1)))))
        b(x1) -> a(x1)
      Qed