MAYBE Problem: app(x,y) -> helpa(0(),plus(length(x),length(y)),x,y) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) helpa(c,l,ys,zs) -> if(ge(c,l),c,l,ys,zs) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) if(true(),c,l,ys,zs) -> nil() if(false(),c,l,ys,zs) -> helpb(c,l,ys,zs) take(0(),cons(x,xs()),ys) -> x take(0(),nil(),cons(y,ys)) -> y take(s(c),cons(x,xs()),ys) -> take(c,xs(),ys) take(s(c),nil(),cons(y,ys)) -> take(c,nil(),ys) helpb(c,l,ys,zs) -> cons(take(c,ys,zs),helpa(s(c),l,ys,zs)) Proof: DP Processor: DPs: app#(x,y) -> length#(y) app#(x,y) -> length#(x) app#(x,y) -> plus#(length(x),length(y)) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) plus#(x,s(y)) -> plus#(x,y) length#(cons(x,y)) -> length#(y) helpa#(c,l,ys,zs) -> ge#(c,l) helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) ge#(s(x),s(y)) -> ge#(x,y) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) helpb#(c,l,ys,zs) -> take#(c,ys,zs) TRS: app(x,y) -> helpa(0(),plus(length(x),length(y)),x,y) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) helpa(c,l,ys,zs) -> if(ge(c,l),c,l,ys,zs) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) if(true(),c,l,ys,zs) -> nil() if(false(),c,l,ys,zs) -> helpb(c,l,ys,zs) take(0(),cons(x,xs()),ys) -> x take(0(),nil(),cons(y,ys)) -> y take(s(c),cons(x,xs()),ys) -> take(c,xs(),ys) take(s(c),nil(),cons(y,ys)) -> take(c,nil(),ys) helpb(c,l,ys,zs) -> cons(take(c,ys,zs),helpa(s(c),l,ys,zs)) Usable Rule Processor: DPs: app#(x,y) -> length#(y) app#(x,y) -> length#(x) app#(x,y) -> plus#(length(x),length(y)) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) plus#(x,s(y)) -> plus#(x,y) length#(cons(x,y)) -> length#(y) helpa#(c,l,ys,zs) -> ge#(c,l) helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) ge#(s(x),s(y)) -> ge#(x,y) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) helpb#(c,l,ys,zs) -> take#(c,ys,zs) TRS: f23(x,y) -> x f23(x,y) -> y length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) TDG Processor: DPs: app#(x,y) -> length#(y) app#(x,y) -> length#(x) app#(x,y) -> plus#(length(x),length(y)) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) plus#(x,s(y)) -> plus#(x,y) length#(cons(x,y)) -> length#(y) helpa#(c,l,ys,zs) -> ge#(c,l) helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) ge#(s(x),s(y)) -> ge#(x,y) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) helpb#(c,l,ys,zs) -> take#(c,ys,zs) TRS: f23(x,y) -> x f23(x,y) -> y length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) graph: take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) -> take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) -> take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) -> take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) -> take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) helpb#(c,l,ys,zs) -> take#(c,ys,zs) -> take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) helpb#(c,l,ys,zs) -> take#(c,ys,zs) -> take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) -> helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) -> helpa#(c,l,ys,zs) -> ge#(c,l) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) -> helpb#(c,l,ys,zs) -> take#(c,ys,zs) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) -> helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) ge#(s(x),s(y)) -> ge#(x,y) -> ge#(s(x),s(y)) -> ge#(x,y) helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) -> if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) helpa#(c,l,ys,zs) -> ge#(c,l) -> ge#(s(x),s(y)) -> ge#(x,y) plus#(x,s(y)) -> plus#(x,y) -> plus#(x,s(y)) -> plus#(x,y) length#(cons(x,y)) -> length#(y) -> length#(cons(x,y)) -> length#(y) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) -> helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) -> helpa#(c,l,ys,zs) -> ge#(c,l) app#(x,y) -> plus#(length(x),length(y)) -> plus#(x,s(y)) -> plus#(x,y) app#(x,y) -> length#(y) -> length#(cons(x,y)) -> length#(y) app#(x,y) -> length#(x) -> length#(cons(x,y)) -> length#(y) EDG Processor: DPs: app#(x,y) -> length#(y) app#(x,y) -> length#(x) app#(x,y) -> plus#(length(x),length(y)) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) plus#(x,s(y)) -> plus#(x,y) length#(cons(x,y)) -> length#(y) helpa#(c,l,ys,zs) -> ge#(c,l) helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) ge#(s(x),s(y)) -> ge#(x,y) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) helpb#(c,l,ys,zs) -> take#(c,ys,zs) TRS: f23(x,y) -> x f23(x,y) -> y length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) graph: take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) -> take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) helpb#(c,l,ys,zs) -> take#(c,ys,zs) -> take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) helpb#(c,l,ys,zs) -> take#(c,ys,zs) -> take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) -> helpa#(c,l,ys,zs) -> ge#(c,l) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) -> helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) -> helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) -> helpb#(c,l,ys,zs) -> take#(c,ys,zs) ge#(s(x),s(y)) -> ge#(x,y) -> ge#(s(x),s(y)) -> ge#(x,y) helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) -> if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) helpa#(c,l,ys,zs) -> ge#(c,l) -> ge#(s(x),s(y)) -> ge#(x,y) plus#(x,s(y)) -> plus#(x,y) -> plus#(x,s(y)) -> plus#(x,y) length#(cons(x,y)) -> length#(y) -> length#(cons(x,y)) -> length#(y) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) -> helpa#(c,l,ys,zs) -> ge#(c,l) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) -> helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) app#(x,y) -> plus#(length(x),length(y)) -> plus#(x,s(y)) -> plus#(x,y) app#(x,y) -> length#(y) -> length#(cons(x,y)) -> length#(y) app#(x,y) -> length#(x) -> length#(cons(x,y)) -> length#(y) Restore Modifier: DPs: app#(x,y) -> length#(y) app#(x,y) -> length#(x) app#(x,y) -> plus#(length(x),length(y)) app#(x,y) -> helpa#(0(),plus(length(x),length(y)),x,y) plus#(x,s(y)) -> plus#(x,y) length#(cons(x,y)) -> length#(y) helpa#(c,l,ys,zs) -> ge#(c,l) helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) ge#(s(x),s(y)) -> ge#(x,y) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) take#(s(c),cons(x,xs()),ys) -> take#(c,xs(),ys) take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) helpb#(c,l,ys,zs) -> take#(c,ys,zs) TRS: app(x,y) -> helpa(0(),plus(length(x),length(y)),x,y) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) helpa(c,l,ys,zs) -> if(ge(c,l),c,l,ys,zs) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) if(true(),c,l,ys,zs) -> nil() if(false(),c,l,ys,zs) -> helpb(c,l,ys,zs) take(0(),cons(x,xs()),ys) -> x take(0(),nil(),cons(y,ys)) -> y take(s(c),cons(x,xs()),ys) -> take(c,xs(),ys) take(s(c),nil(),cons(y,ys)) -> take(c,nil(),ys) helpb(c,l,ys,zs) -> cons(take(c,ys,zs),helpa(s(c),l,ys,zs)) SCC Processor: #sccs: 5 #rules: 7 #arcs: 17/196 DPs: length#(cons(x,y)) -> length#(y) TRS: app(x,y) -> helpa(0(),plus(length(x),length(y)),x,y) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) helpa(c,l,ys,zs) -> if(ge(c,l),c,l,ys,zs) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) if(true(),c,l,ys,zs) -> nil() if(false(),c,l,ys,zs) -> helpb(c,l,ys,zs) take(0(),cons(x,xs()),ys) -> x take(0(),nil(),cons(y,ys)) -> y take(s(c),cons(x,xs()),ys) -> take(c,xs(),ys) take(s(c),nil(),cons(y,ys)) -> take(c,nil(),ys) helpb(c,l,ys,zs) -> cons(take(c,ys,zs),helpa(s(c),l,ys,zs)) Open DPs: plus#(x,s(y)) -> plus#(x,y) TRS: app(x,y) -> helpa(0(),plus(length(x),length(y)),x,y) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) helpa(c,l,ys,zs) -> if(ge(c,l),c,l,ys,zs) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) if(true(),c,l,ys,zs) -> nil() if(false(),c,l,ys,zs) -> helpb(c,l,ys,zs) take(0(),cons(x,xs()),ys) -> x take(0(),nil(),cons(y,ys)) -> y take(s(c),cons(x,xs()),ys) -> take(c,xs(),ys) take(s(c),nil(),cons(y,ys)) -> take(c,nil(),ys) helpb(c,l,ys,zs) -> cons(take(c,ys,zs),helpa(s(c),l,ys,zs)) Open DPs: helpb#(c,l,ys,zs) -> helpa#(s(c),l,ys,zs) helpa#(c,l,ys,zs) -> if#(ge(c,l),c,l,ys,zs) if#(false(),c,l,ys,zs) -> helpb#(c,l,ys,zs) TRS: app(x,y) -> helpa(0(),plus(length(x),length(y)),x,y) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) helpa(c,l,ys,zs) -> if(ge(c,l),c,l,ys,zs) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) if(true(),c,l,ys,zs) -> nil() if(false(),c,l,ys,zs) -> helpb(c,l,ys,zs) take(0(),cons(x,xs()),ys) -> x take(0(),nil(),cons(y,ys)) -> y take(s(c),cons(x,xs()),ys) -> take(c,xs(),ys) take(s(c),nil(),cons(y,ys)) -> take(c,nil(),ys) helpb(c,l,ys,zs) -> cons(take(c,ys,zs),helpa(s(c),l,ys,zs)) Open DPs: ge#(s(x),s(y)) -> ge#(x,y) TRS: app(x,y) -> helpa(0(),plus(length(x),length(y)),x,y) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) helpa(c,l,ys,zs) -> if(ge(c,l),c,l,ys,zs) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) if(true(),c,l,ys,zs) -> nil() if(false(),c,l,ys,zs) -> helpb(c,l,ys,zs) take(0(),cons(x,xs()),ys) -> x take(0(),nil(),cons(y,ys)) -> y take(s(c),cons(x,xs()),ys) -> take(c,xs(),ys) take(s(c),nil(),cons(y,ys)) -> take(c,nil(),ys) helpb(c,l,ys,zs) -> cons(take(c,ys,zs),helpa(s(c),l,ys,zs)) Open DPs: take#(s(c),nil(),cons(y,ys)) -> take#(c,nil(),ys) TRS: app(x,y) -> helpa(0(),plus(length(x),length(y)),x,y) plus(x,0()) -> x plus(x,s(y)) -> s(plus(x,y)) length(nil()) -> 0() length(cons(x,y)) -> s(length(y)) helpa(c,l,ys,zs) -> if(ge(c,l),c,l,ys,zs) ge(x,0()) -> true() ge(0(),s(x)) -> false() ge(s(x),s(y)) -> ge(x,y) if(true(),c,l,ys,zs) -> nil() if(false(),c,l,ys,zs) -> helpb(c,l,ys,zs) take(0(),cons(x,xs()),ys) -> x take(0(),nil(),cons(y,ys)) -> y take(s(c),cons(x,xs()),ys) -> take(c,xs(),ys) take(s(c),nil(),cons(y,ys)) -> take(c,nil(),ys) helpb(c,l,ys,zs) -> cons(take(c,ys,zs),helpa(s(c),l,ys,zs)) Open