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Recognized function symbols in input:

  name                arity   strict-pos  binder-arity        
  ----                -----   -----       -----               
  fun                 1       [1]         [0]                 

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Input Problem:
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Gamma ={
  U1 =?= (fun U2),
  U2 =?= (fun U3),
  U3 =?= (fun U4),
  U4 =?= (fun U5),
  U5 =?= (fun U1)}
Delta1=  {}
Delta2=  {}
Delta3=  {}

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NO SOLUTION!