Input TRS: 1: ack(0(),y) -> s(y) 2: ack(s(x),0()) -> ack(x,s(0())) 3: ack(s(x),s(y)) -> ack(x,ack(s(x),y)) Number of strict rules: 3 Direct Order(PosReal,>,Poly) ... failed. Freezing ack 1: ack❆1_0(y) -> s(y) 2: ack❆1_s(x,0()) -> ack(x,s(0())) 3: ack❆1_s(x,s(y)) -> ack(x,ack❆1_s(x,y)) 4: ack(0(),_1) ->= ack❆1_0(_1) 5: ack(s(_1),_2) ->= ack❆1_s(_1,_2) Number of strict rules: 3 Direct Order(PosReal,>,Poly) ... failed. Dependency Pairs: #1: #ack❆1_s(x,0()) -> #ack(x,s(0())) #2: #ack(s(_1),_2) ->? #ack❆1_s(_1,_2) #3: #ack❆1_s(x,s(y)) -> #ack(x,ack❆1_s(x,y)) #4: #ack❆1_s(x,s(y)) -> #ack❆1_s(x,y) #5: #ack(0(),_1) ->? #ack❆1_0(_1) Number of SCCs: 1, DPs: 4, edges: 8 SCC { #1..4 } Removing DPs: Order(PosReal,>,Sum)... succeeded. s(x1) weight: (/ 1 2) + x1 ack(x1,x2) weight: (/ 1 4) #ack❆1_0(x1) weight: 0 0() weight: 0 ack❆1_0(x1) weight: (/ 3 8) #ack(x1,x2) weight: x1 ack❆1_s(x1,x2) weight: (/ 1 8) + x1 + x2 #ack❆1_s(x1,x2) weight: (/ 1 8) + x1 Usable rules: { } Removed DPs: #1..3 Number of SCCs: 1, DPs: 1, edges: 1 SCC { #4 } Removing DPs: Order(PosReal,>,Sum)... succeeded. s(x1) weight: (/ 1 2) + x1 ack(x1,x2) weight: (/ 1 4) #ack❆1_0(x1) weight: 0 0() weight: 0 ack❆1_0(x1) weight: (/ 3 8) #ack(x1,x2) weight: 0 ack❆1_s(x1,x2) weight: (/ 1 8) + x1 + x2 #ack❆1_s(x1,x2) weight: (/ 1 8) + x2 Usable rules: { } Removed DPs: #4 Number of SCCs: 0, DPs: 0, edges: 0 YES