Consider the TRS R consisting of the rewrite rules 1: c(0,x) -> x 2: c(x,c(y,z)) -> c(x + y,z) 3: 0 + 0 -> 0 4: 0 + 1 -> 1 5: 0 + 2 -> 2 6: 0 + 3 -> 3 7: 0 + 4 -> 4 8: 0 + 5 -> 5 9: 0 + 6 -> 6 10: 0 + 7 -> 7 11: 0 + 8 -> 8 12: 0 + 9 -> 9 13: 1 + 0 -> 1 14: 1 + 1 -> 2 15: 1 + 2 -> 3 16: 1 + 3 -> 4 17: 1 + 4 -> 5 18: 1 + 5 -> 6 19: 1 + 6 -> 7 20: 1 + 7 -> 8 21: 1 + 8 -> 9 22: 1 + 9 -> c(1,0) 23: 2 + 0 -> 2 24: 2 + 1 -> 3 25: 2 + 2 -> 4 26: 2 + 3 -> 5 27: 2 + 4 -> 6 28: 2 + 5 -> 7 29: 2 + 6 -> 8 30: 2 + 7 -> 9 31: 2 + 8 -> c(1,0) 32: 2 + 9 -> c(1,1) 33: 3 + 0 -> 3 34: 3 + 1 -> 4 35: 3 + 2 -> 5 36: 3 + 3 -> 6 37: 3 + 4 -> 7 38: 3 + 5 -> 8 39: 3 + 6 -> 9 40: 3 + 7 -> c(1,0) 41: 3 + 8 -> c(1,1) 42: 3 + 9 -> c(1,2) 43: 4 + 0 -> 4 44: 4 + 1 -> 5 45: 4 + 2 -> 6 46: 4 + 3 -> 7 47: 4 + 4 -> 8 48: 4 + 5 -> 9 49: 4 + 6 -> c(1,0) 50: 4 + 7 -> c(1,1) 51: 4 + 8 -> c(1,2) 52: 4 + 9 -> c(1,3) 53: 5 + 0 -> 5 54: 5 + 1 -> 6 55: 5 + 2 -> 7 56: 5 + 3 -> 8 57: 5 + 4 -> 9 58: 5 + 5 -> c(1,0) 59: 5 + 6 -> c(1,1) 60: 5 + 7 -> c(1,2) 61: 5 + 8 -> c(1,3) 62: 5 + 9 -> c(1,4) 63: 6 + 0 -> 6 64: 6 + 1 -> 7 65: 6 + 2 -> 8 66: 6 + 3 -> 9 67: 6 + 4 -> c(1,0) 68: 6 + 5 -> c(1,1) 69: 6 + 6 -> c(1,2) 70: 6 + 7 -> c(1,3) 71: 6 + 8 -> c(1,4) 72: 6 + 9 -> c(1,5) 73: 7 + 0 -> 7 74: 7 + 1 -> 8 75: 7 + 2 -> 9 76: 7 + 3 -> c(1,0) 77: 7 + 4 -> c(1,1) 78: 7 + 5 -> c(1,2) 79: 7 + 6 -> c(1,3) 80: 7 + 7 -> c(1,4) 81: 7 + 8 -> c(1,5) 82: 7 + 9 -> c(1,6) 83: 8 + 0 -> 8 84: 8 + 1 -> 9 85: 8 + 2 -> c(1,0) 86: 8 + 3 -> c(1,1) 87: 8 + 4 -> c(1,2) 88: 8 + 5 -> c(1,3) 89: 8 + 6 -> c(1,4) 90: 8 + 7 -> c(1,5) 91: 8 + 8 -> c(1,6) 92: 8 + 9 -> c(1,7) 93: 9 + 0 -> 9 94: 9 + 1 -> c(1,0) 95: 9 + 2 -> c(1,1) 96: 9 + 3 -> c(1,2) 97: 9 + 4 -> c(1,3) 98: 9 + 5 -> c(1,4) 99: 9 + 6 -> c(1,5) 100: 9 + 7 -> c(1,6) 101: 9 + 8 -> c(1,7) 102: 9 + 9 -> c(1,8) 103: x + c(y,z) -> c(y,x + z) 104: c(x,y) + z -> c(x,y + z) 105: 0 * 0 -> 0 106: 0 * 1 -> 0 107: 0 * 2 -> 0 108: 0 * 3 -> 0 109: 0 * 4 -> 0 110: 0 * 5 -> 0 111: 0 * 6 -> 0 112: 0 * 7 -> 0 113: 0 * 8 -> 0 114: 0 * 9 -> 0 115: 1 * 0 -> 0 116: 1 * 1 -> 1 117: 1 * 2 -> 2 118: 1 * 3 -> 3 119: 1 * 4 -> 4 120: 1 * 5 -> 5 121: 1 * 6 -> 6 122: 1 * 7 -> 7 123: 1 * 8 -> 8 124: 1 * 9 -> 9 125: 2 * 0 -> 0 126: 2 * 1 -> 2 127: 2 * 2 -> 4 128: 2 * 3 -> 6 129: 2 * 4 -> 8 130: 2 * 5 -> c(1,0) 131: 2 * 6 -> c(1,2) 132: 2 * 7 -> c(1,4) 133: 2 * 8 -> c(1,6) 134: 2 * 9 -> c(1,8) 135: 3 * 0 -> 0 136: 3 * 1 -> 3 137: 3 * 2 -> 6 138: 3 * 3 -> 9 139: 3 * 4 -> c(1,2) 140: 3 * 5 -> c(1,5) 141: 3 * 6 -> c(1,8) 142: 3 * 7 -> c(2,1) 143: 3 * 8 -> c(2,4) 144: 3 * 9 -> c(2,7) 145: 4 * 0 -> 0 146: 4 * 1 -> 4 147: 4 * 2 -> 8 148: 4 * 3 -> c(1,2) 149: 4 * 4 -> c(1,6) 150: 4 * 5 -> c(2,0) 151: 4 * 6 -> c(2,4) 152: 4 * 7 -> c(2,8) 153: 4 * 8 -> c(3,2) 154: 4 * 9 -> c(3,6) 155: 5 * 0 -> 0 156: 5 * 1 -> 5 157: 5 * 2 -> c(1,0) 158: 5 * 3 -> c(1,5) 159: 5 * 4 -> c(2,0) 160: 5 * 5 -> c(2,5) 161: 5 * 6 -> c(3,0) 162: 5 * 7 -> c(3,5) 163: 5 * 8 -> c(4,0) 164: 5 * 9 -> c(4,5) 165: 6 * 0 -> 0 166: 6 * 1 -> 6 167: 6 * 2 -> c(1,2) 168: 6 * 3 -> c(1,8) 169: 6 * 4 -> c(2,4) 170: 6 * 5 -> c(3,0) 171: 6 * 6 -> c(3,6) 172: 6 * 7 -> c(4,2) 173: 6 * 8 -> c(4,8) 174: 6 * 9 -> c(5,4) 175: 7 * 0 -> 0 176: 7 * 1 -> 7 177: 7 * 2 -> c(1,4) 178: 7 * 3 -> c(2,1) 179: 7 * 4 -> c(2,8) 180: 7 * 5 -> c(3,5) 181: 7 * 6 -> c(4,2) 182: 7 * 7 -> c(4,9) 183: 7 * 8 -> c(5,6) 184: 7 * 9 -> c(6,3) 185: 8 * 0 -> 0 186: 8 * 1 -> 8 187: 8 * 2 -> c(1,8) 188: 8 * 3 -> c(2,4) 189: 8 * 4 -> c(3,2) 190: 8 * 5 -> c(4,0) 191: 8 * 6 -> c(4,8) 192: 8 * 7 -> c(5,6) 193: 8 * 8 -> c(6,4) 194: 8 * 9 -> c(7,2) 195: 9 * 0 -> 0 196: 9 * 1 -> 9 197: 9 * 2 -> c(1,8) 198: 9 * 3 -> c(2,7) 199: 9 * 4 -> c(3,6) 200: 9 * 5 -> c(4,5) 201: 9 * 6 -> c(5,4) 202: 9 * 7 -> c(6,3) 203: 9 * 8 -> c(7,2) 204: 9 * 9 -> c(8,1) 205: x * c(y,z) -> c(x * y,x * z) 206: c(x,y) * z -> c(x * z,y * z) There are 115 dependency pairs: 207: C(x,c(y,z)) -> C(x + y,z) 208: C(x,c(y,z)) -> x +# y 209: 1 +# 9 -> C(1,0) 210: 2 +# 8 -> C(1,0) 211: 2 +# 9 -> C(1,1) 212: 3 +# 7 -> C(1,0) 213: 3 +# 8 -> C(1,1) 214: 3 +# 9 -> C(1,2) 215: 4 +# 6 -> C(1,0) 216: 4 +# 7 -> C(1,1) 217: 4 +# 8 -> C(1,2) 218: 4 +# 9 -> C(1,3) 219: 5 +# 5 -> C(1,0) 220: 5 +# 6 -> C(1,1) 221: 5 +# 7 -> C(1,2) 222: 5 +# 8 -> C(1,3) 223: 5 +# 9 -> C(1,4) 224: 6 +# 4 -> C(1,0) 225: 6 +# 5 -> C(1,1) 226: 6 +# 6 -> C(1,2) 227: 6 +# 7 -> C(1,3) 228: 6 +# 8 -> C(1,4) 229: 6 +# 9 -> C(1,5) 230: 7 +# 3 -> C(1,0) 231: 7 +# 4 -> C(1,1) 232: 7 +# 5 -> C(1,2) 233: 7 +# 6 -> C(1,3) 234: 7 +# 7 -> C(1,4) 235: 7 +# 8 -> C(1,5) 236: 7 +# 9 -> C(1,6) 237: 8 +# 2 -> C(1,0) 238: 8 +# 3 -> C(1,1) 239: 8 +# 4 -> C(1,2) 240: 8 +# 5 -> C(1,3) 241: 8 +# 6 -> C(1,4) 242: 8 +# 7 -> C(1,5) 243: 8 +# 8 -> C(1,6) 244: 8 +# 9 -> C(1,7) 245: 9 +# 1 -> C(1,0) 246: 9 +# 2 -> C(1,1) 247: 9 +# 3 -> C(1,2) 248: 9 +# 4 -> C(1,3) 249: 9 +# 5 -> C(1,4) 250: 9 +# 6 -> C(1,5) 251: 9 +# 7 -> C(1,6) 252: 9 +# 8 -> C(1,7) 253: 9 +# 9 -> C(1,8) 254: x +# c(y,z) -> C(y,x + z) 255: x +# c(y,z) -> x +# z 256: c(x,y) +# z -> C(x,y + z) 257: c(x,y) +# z -> y +# z 258: 2 *# 5 -> C(1,0) 259: 2 *# 6 -> C(1,2) 260: 2 *# 7 -> C(1,4) 261: 2 *# 8 -> C(1,6) 262: 2 *# 9 -> C(1,8) 263: 3 *# 4 -> C(1,2) 264: 3 *# 5 -> C(1,5) 265: 3 *# 6 -> C(1,8) 266: 3 *# 7 -> C(2,1) 267: 3 *# 8 -> C(2,4) 268: 3 *# 9 -> C(2,7) 269: 4 *# 3 -> C(1,2) 270: 4 *# 4 -> C(1,6) 271: 4 *# 5 -> C(2,0) 272: 4 *# 6 -> C(2,4) 273: 4 *# 7 -> C(2,8) 274: 4 *# 8 -> C(3,2) 275: 4 *# 9 -> C(3,6) 276: 5 *# 2 -> C(1,0) 277: 5 *# 3 -> C(1,5) 278: 5 *# 4 -> C(2,0) 279: 5 *# 5 -> C(2,5) 280: 5 *# 6 -> C(3,0) 281: 5 *# 7 -> C(3,5) 282: 5 *# 8 -> C(4,0) 283: 5 *# 9 -> C(4,5) 284: 6 *# 2 -> C(1,2) 285: 6 *# 3 -> C(1,8) 286: 6 *# 4 -> C(2,4) 287: 6 *# 5 -> C(3,0) 288: 6 *# 6 -> C(3,6) 289: 6 *# 7 -> C(4,2) 290: 6 *# 8 -> C(4,8) 291: 6 *# 9 -> C(5,4) 292: 7 *# 2 -> C(1,4) 293: 7 *# 3 -> C(2,1) 294: 7 *# 4 -> C(2,8) 295: 7 *# 5 -> C(3,5) 296: 7 *# 6 -> C(4,2) 297: 7 *# 7 -> C(4,9) 298: 7 *# 8 -> C(5,6) 299: 7 *# 9 -> C(6,3) 300: 8 *# 2 -> C(1,8) 301: 8 *# 3 -> C(2,4) 302: 8 *# 4 -> C(3,2) 303: 8 *# 5 -> C(4,0) 304: 8 *# 6 -> C(4,8) 305: 8 *# 7 -> C(5,6) 306: 8 *# 8 -> C(6,4) 307: 8 *# 9 -> C(7,2) 308: 9 *# 2 -> C(1,8) 309: 9 *# 3 -> C(2,7) 310: 9 *# 4 -> C(3,6) 311: 9 *# 5 -> C(4,5) 312: 9 *# 6 -> C(5,4) 313: 9 *# 7 -> C(6,3) 314: 9 *# 8 -> C(7,2) 315: 9 *# 9 -> C(8,1) 316: x *# c(y,z) -> C(x * y,x * z) 317: x *# c(y,z) -> x *# y 318: x *# c(y,z) -> x *# z 319: c(x,y) *# z -> C(x * z,y * z) 320: c(x,y) *# z -> x *# z 321: c(x,y) *# z -> y *# z The approximated dependency graph contains 2 SCCs: {207,208,254-257} and {317,318,320,321}. - Consider the SCC {207,208,254-257}. The usable rules are {1-104}. By taking the polynomial interpretation [0] = [1] = [2] = [3] = [4] = [5] = [6] = [7] = [8] = [9] = 1 and [+](x,y) = [+#](x,y) = [c](x,y) = [C](x,y) = x + y + 1, the rules in {2,22,31,32,40-42,49-52,58-62,67-72,76-82,85-92,94-104,207,254,256} are weakly decreasing and the rules in {1,3-21,23-30,33-39,43-48,53-57,63-66,73-75,83,84,93,208,255,257} are strictly decreasing. There is one new SCC. - Consider the SCC {207}. By taking the polynomial interpretation [0] = [1] = [2] = [3] = [4] = [5] = [6] = [7] = [8] = [9] = 1, [+](x,y) = [c](x,y) = x + y + 1 and [C](x,y) = y + 1, the rules in {2,22,31,32,40-42,49-52,58-62,67-72,76-82,85-92,94-104} are weakly decreasing and the rules in {1,3-21,23-30,33-39,43-48,53-57,63-66,73-75,83,84,93,207} are strictly decreasing. - Consider the SCC {317,318,320,321}. There are no usable rules. By taking the polynomial interpretation [*#](x,y) = [c](x,y) = x + y + 1, the rules in {317,318,320,321} are strictly decreasing. Hence the TRS is terminating.