YES We show the termination of the TRS R: .(|1|(),x) -> x .(x,|1|()) -> x .(i(x),x) -> |1|() .(x,i(x)) -> |1|() i(|1|()) -> |1|() i(i(x)) -> x .(i(y),.(y,z)) -> z .(y,.(i(y),z)) -> z .(.(x,y),z) -> .(x,.(y,z)) i(.(x,y)) -> .(i(y),i(x)) -- SCC decomposition. Consider the dependency pair problem (P, R), where P consists of p1: .#(.(x,y),z) -> .#(x,.(y,z)) p2: .#(.(x,y),z) -> .#(y,z) p3: i#(.(x,y)) -> .#(i(y),i(x)) p4: i#(.(x,y)) -> i#(y) p5: i#(.(x,y)) -> i#(x) and R consists of: r1: .(|1|(),x) -> x r2: .(x,|1|()) -> x r3: .(i(x),x) -> |1|() r4: .(x,i(x)) -> |1|() r5: i(|1|()) -> |1|() r6: i(i(x)) -> x r7: .(i(y),.(y,z)) -> z r8: .(y,.(i(y),z)) -> z r9: .(.(x,y),z) -> .(x,.(y,z)) r10: i(.(x,y)) -> .(i(y),i(x)) The estimated dependency graph contains the following SCCs: {p4, p5} {p1, p2} -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: i#(.(x,y)) -> i#(x) p2: i#(.(x,y)) -> i#(y) and R consists of: r1: .(|1|(),x) -> x r2: .(x,|1|()) -> x r3: .(i(x),x) -> |1|() r4: .(x,i(x)) -> |1|() r5: i(|1|()) -> |1|() r6: i(i(x)) -> x r7: .(i(y),.(y,z)) -> z r8: .(y,.(i(y),z)) -> z r9: .(.(x,y),z) -> .(x,.(y,z)) r10: i(.(x,y)) -> .(i(y),i(x)) The set of usable rules consists of (no rules) Take the reduction pair: matrix interpretations: carrier: N^3 order: lexicographic order interpretations: i#_A(x1) = ((1,0,0),(0,1,0),(1,1,1)) x1 ._A(x1,x2) = ((1,0,0),(1,1,0),(1,1,0)) x1 + ((1,0,0),(1,1,0),(1,1,1)) x2 + (1,0,1) The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains. -- Reduction pair. Consider the dependency pair problem (P, R), where P consists of p1: .#(.(x,y),z) -> .#(x,.(y,z)) p2: .#(.(x,y),z) -> .#(y,z) and R consists of: r1: .(|1|(),x) -> x r2: .(x,|1|()) -> x r3: .(i(x),x) -> |1|() r4: .(x,i(x)) -> |1|() r5: i(|1|()) -> |1|() r6: i(i(x)) -> x r7: .(i(y),.(y,z)) -> z r8: .(y,.(i(y),z)) -> z r9: .(.(x,y),z) -> .(x,.(y,z)) r10: i(.(x,y)) -> .(i(y),i(x)) The set of usable rules consists of r1, r2, r3, r4, r7, r8, r9 Take the reduction pair: matrix interpretations: carrier: N^3 order: lexicographic order interpretations: .#_A(x1,x2) = ((1,0,0),(0,1,0),(1,0,1)) x1 ._A(x1,x2) = x1 + ((1,0,0),(1,0,0),(1,1,0)) x2 + (1,2,1) |1|_A() = (1,4,4) i_A(x1) = ((1,0,0),(0,1,0),(1,1,1)) x1 + (1,1,4) The next rules are strictly ordered: p1, p2 We remove them from the problem. Then no dependency pair remains.