| 1: | minus(x,0) | → x | |
| 2: | minus(s(x),s(y)) | → minus(x,y) | |
| 3: | quot(0,s(y)) | → 0 | |
| 4: | quot(s(x),s(y)) | → s(quot(minus(x,y),s(y))) | |
| 5: | plus(0,y) | → y | |
| 6: | plus(s(x),y) | → s(plus(x,y)) | |
| 7: | plus(minus(x,s(0)),minus(y,s(s(z)))) | → plus(minus(y,s(s(z))),minus(x,s(0))) | |
| 8: | MINUS(s(x),s(y)) | → MINUS(x,y) | |
| 9: | QUOT(s(x),s(y)) | → QUOT(minus(x,y),s(y)) | |
| 10: | QUOT(s(x),s(y)) | → MINUS(x,y) | |
| 11: | PLUS(s(x),y) | → PLUS(x,y) | |
| 12: | PLUS(minus(x,s(0)),minus(y,s(s(z)))) | → PLUS(minus(y,s(s(z))),minus(x,s(0))) | |