YES

Succeeded in reading "/export/starexec/sandbox/benchmark/theBenchmark.ari".
    (CONDITIONTYPE ORIENTED)
    (VAR x)
    (RULES
      f(x) -> a | a == x
      f(x) -> b | b == x
    )

No "->="-rules.

Decomposed conditions and removed infeasible rules if possible.
    (VAR x)
    (RULES
      f(a) -> a
      f(b) -> b
    )

(VAR x)
(CONDITION 
a == x, b == x
)

Optimized the infeasibility problem if possible.

(CONDITION 
b == a
)

This is ultra-RL and deterministic.

This is operationally terminating and confluent.

(RTG_of_NARROWINGTREE
(START
  Gamma[b == a : { e, 1 }]
)
(NONTERMINALS
  Gamma[b == a : { e, 1 }]
)
(RULES
  Gamma[b == a : { e, 1 }] -> EmptySet
)
)

YES