MAYBE * Step 1: DependencyPairs MAYBE + Considered Problem: - Strict TRS: div(x,y) -> ify(ge(y,s(0())),x,y) ge(0(),0()) -> true() ge(0(),s(0())) -> false() ge(0(),s(s(x))) -> ge(0(),s(x)) ge(s(x),0()) -> ge(x,0()) ge(s(x),s(y)) -> ge(x,y) if(false(),x,y) -> 0() if(true(),x,y) -> s(div(minus(x,y),y)) ify(false(),x,y) -> divByZeroError() ify(true(),x,y) -> if(ge(x,y),x,y) minus(0(),0()) -> 0() minus(0(),s(x)) -> minus(0(),x) minus(s(x),0()) -> s(minus(x,0())) minus(s(x),s(y)) -> minus(x,y) plus(0(),0()) -> 0() plus(0(),s(x)) -> s(plus(0(),x)) plus(s(x),y) -> s(plus(x,y)) - Signature: {div/2,ge/2,if/3,ify/3,minus/2,plus/2} / {0/0,divByZeroError/0,false/0,s/1,true/0} - Obligation: innermost runtime complexity wrt. defined symbols {div,ge,if,ify,minus,plus} and constructors {0 ,divByZeroError,false,s,true} + Applied Processor: DependencyPairs {dpKind_ = DT} + Details: We add the following dependency tuples: Strict DPs div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))) ge#(0(),0()) -> c_2() ge#(0(),s(0())) -> c_3() ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))) ge#(s(x),0()) -> c_5(ge#(x,0())) ge#(s(x),s(y)) -> c_6(ge#(x,y)) if#(false(),x,y) -> c_7() if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)) ify#(false(),x,y) -> c_9() ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)) minus#(0(),0()) -> c_11() minus#(0(),s(x)) -> c_12(minus#(0(),x)) minus#(s(x),0()) -> c_13(minus#(x,0())) minus#(s(x),s(y)) -> c_14(minus#(x,y)) plus#(0(),0()) -> c_15() plus#(0(),s(x)) -> c_16(plus#(0(),x)) plus#(s(x),y) -> c_17(plus#(x,y)) Weak DPs and mark the set of starting terms. * Step 2: UsableRules MAYBE + Considered Problem: - Strict DPs: div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))) ge#(0(),0()) -> c_2() ge#(0(),s(0())) -> c_3() ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))) ge#(s(x),0()) -> c_5(ge#(x,0())) ge#(s(x),s(y)) -> c_6(ge#(x,y)) if#(false(),x,y) -> c_7() if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)) ify#(false(),x,y) -> c_9() ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)) minus#(0(),0()) -> c_11() minus#(0(),s(x)) -> c_12(minus#(0(),x)) minus#(s(x),0()) -> c_13(minus#(x,0())) minus#(s(x),s(y)) -> c_14(minus#(x,y)) plus#(0(),0()) -> c_15() plus#(0(),s(x)) -> c_16(plus#(0(),x)) plus#(s(x),y) -> c_17(plus#(x,y)) - Weak TRS: div(x,y) -> ify(ge(y,s(0())),x,y) ge(0(),0()) -> true() ge(0(),s(0())) -> false() ge(0(),s(s(x))) -> ge(0(),s(x)) ge(s(x),0()) -> ge(x,0()) ge(s(x),s(y)) -> ge(x,y) if(false(),x,y) -> 0() if(true(),x,y) -> s(div(minus(x,y),y)) ify(false(),x,y) -> divByZeroError() ify(true(),x,y) -> if(ge(x,y),x,y) minus(0(),0()) -> 0() minus(0(),s(x)) -> minus(0(),x) minus(s(x),0()) -> s(minus(x,0())) minus(s(x),s(y)) -> minus(x,y) plus(0(),0()) -> 0() plus(0(),s(x)) -> s(plus(0(),x)) plus(s(x),y) -> s(plus(x,y)) - Signature: {div/2,ge/2,if/3,ify/3,minus/2,plus/2,div#/2,ge#/2,if#/3,ify#/3,minus#/2,plus#/2} / {0/0,divByZeroError/0 ,false/0,s/1,true/0,c_1/2,c_2/0,c_3/0,c_4/1,c_5/1,c_6/1,c_7/0,c_8/2,c_9/0,c_10/2,c_11/0,c_12/1,c_13/1,c_14/1 ,c_15/0,c_16/1,c_17/1} - Obligation: innermost runtime complexity wrt. defined symbols {div#,ge#,if#,ify#,minus#,plus#} and constructors {0 ,divByZeroError,false,s,true} + Applied Processor: UsableRules + Details: We replace rewrite rules by usable rules: ge(0(),0()) -> true() ge(0(),s(0())) -> false() ge(0(),s(s(x))) -> ge(0(),s(x)) ge(s(x),0()) -> ge(x,0()) ge(s(x),s(y)) -> ge(x,y) minus(0(),0()) -> 0() minus(0(),s(x)) -> minus(0(),x) minus(s(x),0()) -> s(minus(x,0())) minus(s(x),s(y)) -> minus(x,y) div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))) ge#(0(),0()) -> c_2() ge#(0(),s(0())) -> c_3() ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))) ge#(s(x),0()) -> c_5(ge#(x,0())) ge#(s(x),s(y)) -> c_6(ge#(x,y)) if#(false(),x,y) -> c_7() if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)) ify#(false(),x,y) -> c_9() ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)) minus#(0(),0()) -> c_11() minus#(0(),s(x)) -> c_12(minus#(0(),x)) minus#(s(x),0()) -> c_13(minus#(x,0())) minus#(s(x),s(y)) -> c_14(minus#(x,y)) plus#(0(),0()) -> c_15() plus#(0(),s(x)) -> c_16(plus#(0(),x)) plus#(s(x),y) -> c_17(plus#(x,y)) * Step 3: PredecessorEstimation MAYBE + Considered Problem: - Strict DPs: div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))) ge#(0(),0()) -> c_2() ge#(0(),s(0())) -> c_3() ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))) ge#(s(x),0()) -> c_5(ge#(x,0())) ge#(s(x),s(y)) -> c_6(ge#(x,y)) if#(false(),x,y) -> c_7() if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)) ify#(false(),x,y) -> c_9() ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)) minus#(0(),0()) -> c_11() minus#(0(),s(x)) -> c_12(minus#(0(),x)) minus#(s(x),0()) -> c_13(minus#(x,0())) minus#(s(x),s(y)) -> c_14(minus#(x,y)) plus#(0(),0()) -> c_15() plus#(0(),s(x)) -> c_16(plus#(0(),x)) plus#(s(x),y) -> c_17(plus#(x,y)) - Weak TRS: ge(0(),0()) -> true() ge(0(),s(0())) -> false() ge(0(),s(s(x))) -> ge(0(),s(x)) ge(s(x),0()) -> ge(x,0()) ge(s(x),s(y)) -> ge(x,y) minus(0(),0()) -> 0() minus(0(),s(x)) -> minus(0(),x) minus(s(x),0()) -> s(minus(x,0())) minus(s(x),s(y)) -> minus(x,y) - Signature: {div/2,ge/2,if/3,ify/3,minus/2,plus/2,div#/2,ge#/2,if#/3,ify#/3,minus#/2,plus#/2} / {0/0,divByZeroError/0 ,false/0,s/1,true/0,c_1/2,c_2/0,c_3/0,c_4/1,c_5/1,c_6/1,c_7/0,c_8/2,c_9/0,c_10/2,c_11/0,c_12/1,c_13/1,c_14/1 ,c_15/0,c_16/1,c_17/1} - Obligation: innermost runtime complexity wrt. defined symbols {div#,ge#,if#,ify#,minus#,plus#} and constructors {0 ,divByZeroError,false,s,true} + Applied Processor: PredecessorEstimation {onSelection = all simple predecessor estimation selector} + Details: We estimate the number of application of {2,3,7,9,11,15} by application of Pre({2,3,7,9,11,15}) = {1,4,5,6,8,10,12,13,14,16,17}. Here rules are labelled as follows: 1: div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))) 2: ge#(0(),0()) -> c_2() 3: ge#(0(),s(0())) -> c_3() 4: ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))) 5: ge#(s(x),0()) -> c_5(ge#(x,0())) 6: ge#(s(x),s(y)) -> c_6(ge#(x,y)) 7: if#(false(),x,y) -> c_7() 8: if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)) 9: ify#(false(),x,y) -> c_9() 10: ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)) 11: minus#(0(),0()) -> c_11() 12: minus#(0(),s(x)) -> c_12(minus#(0(),x)) 13: minus#(s(x),0()) -> c_13(minus#(x,0())) 14: minus#(s(x),s(y)) -> c_14(minus#(x,y)) 15: plus#(0(),0()) -> c_15() 16: plus#(0(),s(x)) -> c_16(plus#(0(),x)) 17: plus#(s(x),y) -> c_17(plus#(x,y)) * Step 4: RemoveWeakSuffixes MAYBE + Considered Problem: - Strict DPs: div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))) ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))) ge#(s(x),0()) -> c_5(ge#(x,0())) ge#(s(x),s(y)) -> c_6(ge#(x,y)) if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)) ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)) minus#(0(),s(x)) -> c_12(minus#(0(),x)) minus#(s(x),0()) -> c_13(minus#(x,0())) minus#(s(x),s(y)) -> c_14(minus#(x,y)) plus#(0(),s(x)) -> c_16(plus#(0(),x)) plus#(s(x),y) -> c_17(plus#(x,y)) - Weak DPs: ge#(0(),0()) -> c_2() ge#(0(),s(0())) -> c_3() if#(false(),x,y) -> c_7() ify#(false(),x,y) -> c_9() minus#(0(),0()) -> c_11() plus#(0(),0()) -> c_15() - Weak TRS: ge(0(),0()) -> true() ge(0(),s(0())) -> false() ge(0(),s(s(x))) -> ge(0(),s(x)) ge(s(x),0()) -> ge(x,0()) ge(s(x),s(y)) -> ge(x,y) minus(0(),0()) -> 0() minus(0(),s(x)) -> minus(0(),x) minus(s(x),0()) -> s(minus(x,0())) minus(s(x),s(y)) -> minus(x,y) - Signature: {div/2,ge/2,if/3,ify/3,minus/2,plus/2,div#/2,ge#/2,if#/3,ify#/3,minus#/2,plus#/2} / {0/0,divByZeroError/0 ,false/0,s/1,true/0,c_1/2,c_2/0,c_3/0,c_4/1,c_5/1,c_6/1,c_7/0,c_8/2,c_9/0,c_10/2,c_11/0,c_12/1,c_13/1,c_14/1 ,c_15/0,c_16/1,c_17/1} - Obligation: innermost runtime complexity wrt. defined symbols {div#,ge#,if#,ify#,minus#,plus#} and constructors {0 ,divByZeroError,false,s,true} + Applied Processor: RemoveWeakSuffixes + Details: Consider the dependency graph 1:S:div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))) -->_1 ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)):6 -->_2 ge#(s(x),s(y)) -> c_6(ge#(x,y)):4 -->_1 ify#(false(),x,y) -> c_9():15 -->_2 ge#(0(),s(0())) -> c_3():13 2:S:ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))) -->_1 ge#(0(),s(0())) -> c_3():13 -->_1 ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))):2 3:S:ge#(s(x),0()) -> c_5(ge#(x,0())) -->_1 ge#(0(),0()) -> c_2():12 -->_1 ge#(s(x),0()) -> c_5(ge#(x,0())):3 4:S:ge#(s(x),s(y)) -> c_6(ge#(x,y)) -->_1 ge#(0(),s(0())) -> c_3():13 -->_1 ge#(0(),0()) -> c_2():12 -->_1 ge#(s(x),s(y)) -> c_6(ge#(x,y)):4 -->_1 ge#(s(x),0()) -> c_5(ge#(x,0())):3 -->_1 ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))):2 5:S:if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)) -->_2 minus#(s(x),s(y)) -> c_14(minus#(x,y)):9 -->_2 minus#(s(x),0()) -> c_13(minus#(x,0())):8 -->_2 minus#(0(),s(x)) -> c_12(minus#(0(),x)):7 -->_2 minus#(0(),0()) -> c_11():16 -->_1 div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))):1 6:S:ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)) -->_1 if#(false(),x,y) -> c_7():14 -->_2 ge#(0(),s(0())) -> c_3():13 -->_2 ge#(0(),0()) -> c_2():12 -->_1 if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)):5 -->_2 ge#(s(x),s(y)) -> c_6(ge#(x,y)):4 -->_2 ge#(s(x),0()) -> c_5(ge#(x,0())):3 -->_2 ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))):2 7:S:minus#(0(),s(x)) -> c_12(minus#(0(),x)) -->_1 minus#(0(),0()) -> c_11():16 -->_1 minus#(0(),s(x)) -> c_12(minus#(0(),x)):7 8:S:minus#(s(x),0()) -> c_13(minus#(x,0())) -->_1 minus#(0(),0()) -> c_11():16 -->_1 minus#(s(x),0()) -> c_13(minus#(x,0())):8 9:S:minus#(s(x),s(y)) -> c_14(minus#(x,y)) -->_1 minus#(0(),0()) -> c_11():16 -->_1 minus#(s(x),s(y)) -> c_14(minus#(x,y)):9 -->_1 minus#(s(x),0()) -> c_13(minus#(x,0())):8 -->_1 minus#(0(),s(x)) -> c_12(minus#(0(),x)):7 10:S:plus#(0(),s(x)) -> c_16(plus#(0(),x)) -->_1 plus#(0(),0()) -> c_15():17 -->_1 plus#(0(),s(x)) -> c_16(plus#(0(),x)):10 11:S:plus#(s(x),y) -> c_17(plus#(x,y)) -->_1 plus#(0(),0()) -> c_15():17 -->_1 plus#(s(x),y) -> c_17(plus#(x,y)):11 -->_1 plus#(0(),s(x)) -> c_16(plus#(0(),x)):10 12:W:ge#(0(),0()) -> c_2() 13:W:ge#(0(),s(0())) -> c_3() 14:W:if#(false(),x,y) -> c_7() 15:W:ify#(false(),x,y) -> c_9() 16:W:minus#(0(),0()) -> c_11() 17:W:plus#(0(),0()) -> c_15() The following weak DPs constitute a sub-graph of the DG that is closed under successors. The DPs are removed. 17: plus#(0(),0()) -> c_15() 15: ify#(false(),x,y) -> c_9() 16: minus#(0(),0()) -> c_11() 12: ge#(0(),0()) -> c_2() 13: ge#(0(),s(0())) -> c_3() 14: if#(false(),x,y) -> c_7() * Step 5: Failure MAYBE + Considered Problem: - Strict DPs: div#(x,y) -> c_1(ify#(ge(y,s(0())),x,y),ge#(y,s(0()))) ge#(0(),s(s(x))) -> c_4(ge#(0(),s(x))) ge#(s(x),0()) -> c_5(ge#(x,0())) ge#(s(x),s(y)) -> c_6(ge#(x,y)) if#(true(),x,y) -> c_8(div#(minus(x,y),y),minus#(x,y)) ify#(true(),x,y) -> c_10(if#(ge(x,y),x,y),ge#(x,y)) minus#(0(),s(x)) -> c_12(minus#(0(),x)) minus#(s(x),0()) -> c_13(minus#(x,0())) minus#(s(x),s(y)) -> c_14(minus#(x,y)) plus#(0(),s(x)) -> c_16(plus#(0(),x)) plus#(s(x),y) -> c_17(plus#(x,y)) - Weak TRS: ge(0(),0()) -> true() ge(0(),s(0())) -> false() ge(0(),s(s(x))) -> ge(0(),s(x)) ge(s(x),0()) -> ge(x,0()) ge(s(x),s(y)) -> ge(x,y) minus(0(),0()) -> 0() minus(0(),s(x)) -> minus(0(),x) minus(s(x),0()) -> s(minus(x,0())) minus(s(x),s(y)) -> minus(x,y) - Signature: {div/2,ge/2,if/3,ify/3,minus/2,plus/2,div#/2,ge#/2,if#/3,ify#/3,minus#/2,plus#/2} / {0/0,divByZeroError/0 ,false/0,s/1,true/0,c_1/2,c_2/0,c_3/0,c_4/1,c_5/1,c_6/1,c_7/0,c_8/2,c_9/0,c_10/2,c_11/0,c_12/1,c_13/1,c_14/1 ,c_15/0,c_16/1,c_17/1} - Obligation: innermost runtime complexity wrt. defined symbols {div#,ge#,if#,ify#,minus#,plus#} and constructors {0 ,divByZeroError,false,s,true} + Applied Processor: EmptyProcessor + Details: The problem is still open. MAYBE