ceta_eq: termination proof not accepted
1: error below switch to dependency pairs
1.1: error below the dependency graph processor
 could not apply the size-change processor with the following 
  Argument Filter: 
  pi(f/2) = [1,2]
  pi(a/0) = []
  
  RPO with the following precedence
  precedence(f[2]) = 0
  precedence(a[0]) = 0
  
  precedence(_) = 0
  and the following status
  status(f[2]) = mul
  status(a[0]) = mul
  
  status(_) = lex
  
  for the following reason
  problem when orienting usable rules
  could not orient f(a, f(f(a, x), a)) >= f(f(a, f(a, x)), a)
  pi( f(a, f(f(a, x), a)) ) = f(a, f(f(a, x), a))
  pi( f(f(a, f(a, x)), a) ) = f(f(a, f(a, x)), a)
  could not orient f(a, f(f(a, x), a)) >=RPO f(f(a, f(a, x)), a)