YES
0 QTRS
↳1 QTRSRRRProof (⇔, 0 ms)
↳2 QTRS
↳3 RisEmptyProof (⇔, 0 ms)
↳4 YES
dfib(s(s(x)), y) → dfib(s(x), dfib(x, y))
With this ordering the following rules can be removed by the rule removal processor [LPAR04] because they are oriented strictly:
POL(dfib(x1, x2)) = 2·x1 + x2
POL(s(x1)) = 2 + 2·x1
dfib(s(s(x)), y) → dfib(s(x), dfib(x, y))