YES We show the termination of the TRS R: times(x,plus(y,|1|())) -> plus(times(x,plus(y,times(|1|(),|0|()))),x) times(x,|1|()) -> x plus(x,|0|()) -> x times(x,|0|()) -> |0|() -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: times#(x,plus(y,|1|())) -> plus#(times(x,plus(y,times(|1|(),|0|()))),x) p2: times#(x,plus(y,|1|())) -> times#(x,plus(y,times(|1|(),|0|()))) p3: times#(x,plus(y,|1|())) -> plus#(y,times(|1|(),|0|())) p4: times#(x,plus(y,|1|())) -> times#(|1|(),|0|()) and R consists of: r1: times(x,plus(y,|1|())) -> plus(times(x,plus(y,times(|1|(),|0|()))),x) r2: times(x,|1|()) -> x r3: plus(x,|0|()) -> x r4: times(x,|0|()) -> |0|() The estimated dependency graph contains the following SCCs: {p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: times#(x,plus(y,|1|())) -> times#(x,plus(y,times(|1|(),|0|()))) and R consists of: r1: times(x,plus(y,|1|())) -> plus(times(x,plus(y,times(|1|(),|0|()))),x) r2: times(x,|1|()) -> x r3: plus(x,|0|()) -> x r4: times(x,|0|()) -> |0|() The set of usable rules consists of r3, r4 Take the reduction pair: lexicographic combination of reduction pairs: 1. matrix interpretations: carrier: N^4 order: lexicographic order interpretations: times#_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,1,1,1)) x1 + x2 plus_A(x1,x2) = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,0,1,1)) x1 + x2 + (0,1,1,1) |1|_A() = (3,1,1,1) times_A(x1,x2) = (2,0,1,1) |0|_A() = (1,1,2,2) 2. lexicographic path order with precedence: precedence: |1| > times# > plus > times > |0| argument filter: pi(times#) = [1] pi(plus) = [1] pi(|1|) = [] pi(times) = [] pi(|0|) = [] The next rules are strictly ordered: p1 We remove them from the problem. Then no dependency pair remains.