We consider termination of the LCTRS with only rule scheme Calc: Signature: cd :: Bool -> Int -> o Rules: cd(true, x) -> cd(x > 0, x - 1) | x = x The system is accessible function passing by a sort ordering that equates all sorts. We start by computing the initial DP problem D1 = (P1, R, i, c), where: P1. (1) cd#(true, x) => cd#(x > 0, x - 1) | x = x ***** We apply the Usable Rules Processor on D1 = (P1, R, i, c). We obtain 0 usable rules (out of 1 rules in the input problem). Processor output: { D2 = (P1, {}, i, c) }. ***** No progress could be made on DP problem D2 = (P1, {}, i, c).