YES
Did not drop rules.
Inlined conditions for 0 rules.
Left-inlined conditions for 1 rules:
  f(a()) -> c()  | 
Due to Ifrit-method removed 0 infeasible rules.
Did not use redundant rules method.
INFEASIBLE because

problem obtained from input
is proven infeasible
using TCAP on
|(f(b()),c()) ->* |(x,x)

where | is used as a fresh function symbol, since it is illegal in the input format.