YES Problem: c(b(a(a(x1)))) -> a(a(b(a(a(b(c(b(a(c(x1)))))))))) Proof: String Reversal Processor: a(a(b(c(x1)))) -> c(a(b(c(b(a(a(b(a(a(x1)))))))))) Bounds Processor: bound: 2 enrichment: match automaton: final states: {1} transitions: f30() -> 2* c0(11) -> 1* c0(8) -> 9* a0(10) -> 11* a0(5) -> 6* a0(2) -> 3* a0(6) -> 7* a0(3) -> 4* b0(7) -> 8* b0(9) -> 10* b0(4) -> 5* c1(65) -> 66* c1(62) -> 63* c1(54) -> 55* c1(51) -> 52* c1(21) -> 22* c1(18) -> 19* a1(60) -> 61* a1(45) -> 46* a1(20) -> 21* a1(15) -> 16* a1(57) -> 58* a1(12) -> 13* a1(64) -> 65* a1(59) -> 60* a1(49) -> 50* a1(56) -> 57* a1(46) -> 47* a1(16) -> 17* a1(53) -> 54* a1(48) -> 49* a1(13) -> 14* b1(50) -> 51* b1(52) -> 53* b1(47) -> 48* b1(17) -> 18* b1(19) -> 20* b1(14) -> 15* b1(61) -> 62* b1(63) -> 64* b1(58) -> 59* c2(142) -> 143* c2(139) -> 140* c2(109) -> 110* c2(106) -> 107* c2(98) -> 99* c2(95) -> 96* a2(137) -> 138* a2(97) -> 98* a2(92) -> 93* a2(134) -> 135* a2(104) -> 105* a2(89) -> 90* a2(141) -> 142* a2(136) -> 137* a2(101) -> 102* a2(133) -> 134* a2(108) -> 109* a2(103) -> 104* a2(93) -> 94* a2(100) -> 101* a2(90) -> 91* b2(107) -> 108* b2(102) -> 103* b2(94) -> 95* b2(96) -> 97* b2(91) -> 92* b2(138) -> 139* b2(140) -> 141* b2(135) -> 136* b2(105) -> 106* 1 -> 3,4 8 -> 45* 11 -> 12* 18 -> 100* 21 -> 56* 22 -> 7* 55 -> 13* 62 -> 133* 65 -> 89* 66 -> 47* 99 -> 50* 110 -> 57* 143 -> 90* problem: Qed