YES(?,POLY)

'Pop* with parameter subtitution (timeout of 60.0 seconds)'
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Answer:           YES(?,POLY)
Input Problem:    innermost runtime-complexity with respect to
  Rules:
    {  d(x) -> e(u(x))
     , d(u(x)) -> c(x)
     , c(u(x)) -> b(x)
     , v(e(x)) -> x
     , b(u(x)) -> a(e(x))}

Proof Output:    
  The input was oriented with the instance of POP* as induced by the precedence
  
   d ~ c, d ~ b, d ~ v, c ~ b, c ~ v, b ~ v
  
  and safe mapping
  
   safe(d) = {}, safe(e) = {1}, safe(u) = {1}, safe(c) = {},
   safe(b) = {1}, safe(v) = {}, safe(a) = {1} .
  
  For your convenience, here is the input in predicative notation:
  
   Rules:
    {  d(x;) -> e(; u(; x))
     , d(u(; x);) -> c(x;)
     , c(u(; x);) -> b(; x)
     , v(e(; x);) -> x
     , b(; u(; x)) -> a(; e(; x))}