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)) 4: f(s(x),y) -> f(x,s(x)) 5: f(x,s(y)) -> f(y,x) 6: f(x,y) -> ack(x,y) 7: ack(s(x),y) -> f(x,x) Number of strict rules: 7 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: f(s(x),y) -> f(x,s(x)) 5: f(x,s(y)) -> f(y,x) 6: f(x,y) -> ack(x,y) 7: ack❆1_s(x,y) -> f(x,x) 8: ack(|0|(),_1) ->= ack❆1_|0|(_1) 9: ack(s(_1),_2) ->= ack❆1_s(_1,_2) Number of strict rules: 7 Direct Order(PosReal,>,Poly) ... failed. Dependency Pairs: #1: #ack❆1_s(x,|0|()) -> #ack(x,s(|0|())) #2: #f(x,y) -> #ack(x,y) #3: #ack(s(_1),_2) ->? #ack❆1_s(_1,_2) #4: #ack❆1_s(x,y) -> #f(x,x) #5: #f(x,s(y)) -> #f(y,x) #6: #ack❆1_s(x,s(y)) -> #ack(x,ack❆1_s(x,y)) #7: #ack❆1_s(x,s(y)) -> #ack❆1_s(x,y) #8: #ack(|0|(),_1) ->? #ack❆1_|0|(_1) #9: #f(s(x),y) -> #f(x,s(x)) Number of SCCs: 1, DPs: 8, edges: 20 SCC { #1..7 #9 } Removing DPs: Order(PosReal,>,Sum)... Order(PosReal,>,Max)... succeeded. |0|() weight: (/ 1 8) #ack❆1_|0|(x1) weight: 0 s(x1) weight: (/ 3 8) + x1 ack❆1_|0|(x1) weight: (/ 1 8) + x1 ack(x1,x2) weight: 0 f(x1,x2) weight: max{0, (/ 1 4) + x2} #f(x1,x2) weight: max{(/ 1 4) + x2, (/ 3 8) + x1} #ack(x1,x2) weight: max{0, (/ 1 8) + x1} ack❆1_s(x1,x2) weight: max{0, (/ 1 8) + x2} #ack❆1_s(x1,x2) weight: max{0, (/ 3 8) + x1} Usable rules: { } Removed DPs: #1..3 #5 #6 #9 Number of SCCs: 1, DPs: 1, edges: 1 SCC { #7 } Removing DPs: Order(PosReal,>,Sum)... succeeded. |0|() weight: 0 #ack❆1_|0|(x1) weight: 0 s(x1) weight: (/ 1 4) + x1 ack❆1_|0|(x1) weight: (/ 1 8) + x1 ack(x1,x2) weight: x1 f(x1,x2) weight: (/ 1 2) #f(x1,x2) weight: 0 #ack(x1,x2) weight: 0 ack❆1_s(x1,x2) weight: (/ 3 8) + x2 #ack❆1_s(x1,x2) weight: x2 Usable rules: { } Removed DPs: #7 Number of SCCs: 0, DPs: 0, edges: 0 YES