YES Problem: f(x,a(b(c(y)))) -> f(b(c(a(b(x)))),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) f(c(x),y) -> f(x,c(y)) Proof: DP Processor: DPs: f#(x,a(b(c(y)))) -> f#(b(c(a(b(x)))),y) f#(a(x),y) -> f#(x,a(y)) f#(b(x),y) -> f#(x,b(y)) f#(c(x),y) -> f#(x,c(y)) TRS: f(x,a(b(c(y)))) -> f(b(c(a(b(x)))),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) f(c(x),y) -> f(x,c(y)) EDG Processor: DPs: f#(x,a(b(c(y)))) -> f#(b(c(a(b(x)))),y) f#(a(x),y) -> f#(x,a(y)) f#(b(x),y) -> f#(x,b(y)) f#(c(x),y) -> f#(x,c(y)) TRS: f(x,a(b(c(y)))) -> f(b(c(a(b(x)))),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) f(c(x),y) -> f(x,c(y)) graph: f#(a(x),y) -> f#(x,a(y)) -> f#(x,a(b(c(y)))) -> f#(b(c(a(b(x)))),y) f#(a(x),y) -> f#(x,a(y)) -> f#(a(x),y) -> f#(x,a(y)) f#(a(x),y) -> f#(x,a(y)) -> f#(b(x),y) -> f#(x,b(y)) f#(a(x),y) -> f#(x,a(y)) -> f#(c(x),y) -> f#(x,c(y)) f#(b(x),y) -> f#(x,b(y)) -> f#(a(x),y) -> f#(x,a(y)) f#(b(x),y) -> f#(x,b(y)) -> f#(b(x),y) -> f#(x,b(y)) f#(b(x),y) -> f#(x,b(y)) -> f#(c(x),y) -> f#(x,c(y)) f#(c(x),y) -> f#(x,c(y)) -> f#(a(x),y) -> f#(x,a(y)) f#(c(x),y) -> f#(x,c(y)) -> f#(b(x),y) -> f#(x,b(y)) f#(c(x),y) -> f#(x,c(y)) -> f#(c(x),y) -> f#(x,c(y)) f#(x,a(b(c(y)))) -> f#(b(c(a(b(x)))),y) -> f#(x,a(b(c(y)))) -> f#(b(c(a(b(x)))),y) f#(x,a(b(c(y)))) -> f#(b(c(a(b(x)))),y) -> f#(b(x),y) -> f#(x,b(y)) Bounds Processor: bound: 1 enrichment: match-dp automaton: final states: {13} transitions: a1(31) -> 32* f50() -> 14* b1(32) -> 33* b1(33) -> 38* f{#,0}(14,32) -> 13* f{#,0}(25,15) -> 13* f{#,0}(14,38) -> 13* f{#,0}(25,23) -> 13* f{#,0}(26,14) -> 13* f{#,0}(26,38) -> 13* f{#,0}(14,15) -> 13* f{#,0}(14,31) -> 13* f{#,0}(26,15) -> 13* f{#,0}(26,23) -> 13* f{#,0}(26,31) -> 13* c1(15) -> 31* c1(38) -> 31* c1(33) -> 31* c1(23) -> 31* b0(25) -> 26* b0(15) -> 15* b0(14) -> 23* b0(31) -> 15* b0(26) -> 23* b0(38) -> 15* b0(23) -> 15* c0(15) -> 15* c0(32) -> 15* c0(24) -> 25* c0(14) -> 15* c0(31) -> 15* a0(15) -> 15* a0(32) -> 15* a0(26) -> 24* a0(38) -> 15* a0(33) -> 15* a0(23) -> 24* f{#,1}(25,33) -> 13* f{#,1}(26,32) -> 13* f{#,1}(23,32) -> 13* f{#,1}(24,31) -> 13* f{#,1}(14,33) -> 13* f{#,1}(25,38) -> 13* f{#,1}(26,33) -> 13* problem: DPs: f#(x,a(b(c(y)))) -> f#(b(c(a(b(x)))),y) f#(a(x),y) -> f#(x,a(y)) f#(b(x),y) -> f#(x,b(y)) TRS: f(x,a(b(c(y)))) -> f(b(c(a(b(x)))),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) f(c(x),y) -> f(x,c(y)) Matrix Interpretation Processor: dimension: 1 interpretation: [f#](x0, x1) = x1, [f](x0, x1) = 0, [a](x0) = x0, [b](x0) = x0, [c](x0) = x0 + 1 orientation: f#(x,a(b(c(y)))) = y + 1 >= y = f#(b(c(a(b(x)))),y) f#(a(x),y) = y >= y = f#(x,a(y)) f#(b(x),y) = y >= y = f#(x,b(y)) f(x,a(b(c(y)))) = 0 >= 0 = f(b(c(a(b(x)))),y) f(a(x),y) = 0 >= 0 = f(x,a(y)) f(b(x),y) = 0 >= 0 = f(x,b(y)) f(c(x),y) = 0 >= 0 = f(x,c(y)) problem: DPs: f#(a(x),y) -> f#(x,a(y)) f#(b(x),y) -> f#(x,b(y)) TRS: f(x,a(b(c(y)))) -> f(b(c(a(b(x)))),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) f(c(x),y) -> f(x,c(y)) Subterm Criterion Processor: simple projection: pi(f#) = 0 problem: DPs: TRS: f(x,a(b(c(y)))) -> f(b(c(a(b(x)))),y) f(a(x),y) -> f(x,a(y)) f(b(x),y) -> f(x,b(y)) f(c(x),y) -> f(x,c(y)) Qed