YES

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

Proof:
 Bounds Processor:
  bound: 3
  enrichment: match
  automaton:
   final states: {1}
   transitions:
    b0(7) -> 8*
    b0(3) -> 4*
    b0(5) -> 6*
    a3(97) -> 98*
    a3(98) -> 99*
    a3(99) -> 100*
    c3(95) -> 96*
    c3(91) -> 92*
    c3(93) -> 94*
    a1(47) -> 48*
    a1(17) -> 18*
    a1(19) -> 20*
    a1(48) -> 49*
    a1(49) -> 50*
    a1(18) -> 19*
    c0(6) -> 7*
    c0(4) -> 5*
    c0(2) -> 3*
    c2(81) -> 82*
    c2(51) -> 52*
    c2(83) -> 84*
    c2(85) -> 86*
    c2(55) -> 56*
    c2(53) -> 54*
    b2(52) -> 53*
    b2(56) -> 57*
    b2(84) -> 85*
    b2(54) -> 55*
    b2(86) -> 87*
    b2(82) -> 83*
    a0(10) -> 1*
    a0(8) -> 9*
    a0(9) -> 10*
    f30() -> 2*
    b1(16) -> 17*
    b1(44) -> 45*
    b1(12) -> 13*
    b1(46) -> 47*
    b1(14) -> 15*
    b1(42) -> 43*
    a2(57) -> 58*
    a2(89) -> 90*
    a2(59) -> 60*
    a2(87) -> 88*
    a2(88) -> 89*
    a2(58) -> 59*
    c1(43) -> 44*
    c1(13) -> 14*
    c1(15) -> 16*
    c1(45) -> 46*
    c1(41) -> 42*
    c1(11) -> 12*
    b3(92) -> 93*
    b3(94) -> 95*
    b3(96) -> 97*
    19 -> 41*
    17 -> 51*
    48 -> 81*
    100 -> 57*
    88 -> 91*
    60 -> 45*
    1 -> 4,6
    20 -> 8*
    90 -> 53*
    9 -> 11*
    50 -> 15*
  problem:
   
  Qed