Consider the TRS R consisting of the rewrite rules 1: times(x,0) -> 0 2: times(x,s(y)) -> plus(times(x,y),x) 3: plus(x,0) -> x 4: plus(0,x) -> x 5: plus(x,s(y)) -> s(plus(x,y)) 6: plus(s(x),y) -> s(plus(x,y)) There are 4 dependency pairs: 7: TIMES(x,s(y)) -> PLUS(times(x,y),x) 8: TIMES(x,s(y)) -> TIMES(x,y) 9: PLUS(x,s(y)) -> PLUS(x,y) 10: PLUS(s(x),y) -> PLUS(x,y) The approximated dependency graph contains 2 SCCs: {9,10} and {8}. - Consider the SCC {9,10}. There are no usable rules. By taking the polynomial interpretation [s](x) = x + 1 and [PLUS](x,y) = x + y + 1, the rules in {9,10} are strictly decreasing. - Consider the SCC {8}. There are no usable rules. By taking the polynomial interpretation [s](x) = x + 1 and [TIMES](x,y) = x + y + 1, rule 8 is strictly decreasing. Hence the TRS is terminating.