YES We show the termination of the TRS R: -(|0|(),y) -> |0|() -(x,|0|()) -> x -(x,s(y)) -> if(greater(x,s(y)),s(-(x,p(s(y)))),|0|()) p(|0|()) -> |0|() p(s(x)) -> x -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: -#(x,s(y)) -> -#(x,p(s(y))) p2: -#(x,s(y)) -> p#(s(y)) and R consists of: r1: -(|0|(),y) -> |0|() r2: -(x,|0|()) -> x r3: -(x,s(y)) -> if(greater(x,s(y)),s(-(x,p(s(y)))),|0|()) r4: p(|0|()) -> |0|() r5: p(s(x)) -> x The estimated dependency graph contains the following SCCs: {p1} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: -#(x,s(y)) -> -#(x,p(s(y))) and R consists of: r1: -(|0|(),y) -> |0|() r2: -(x,|0|()) -> x r3: -(x,s(y)) -> if(greater(x,s(y)),s(-(x,p(s(y)))),|0|()) r4: p(|0|()) -> |0|() r5: p(s(x)) -> x The set of usable rules consists of r5 Take the reduction pair: matrix interpretations: carrier: N^3 order: lexicographic order interpretations: -#_A(x1,x2) = ((1,0,0),(0,0,0),(0,1,0)) x2 s_A(x1) = ((1,0,0),(0,0,0),(0,1,0)) x1 + (1,2,1) p_A(x1) = x1 + (0,1,1) The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.