Axiom
SECMATeq_dec :
forall x1 x2 : OBJECT * ReadersWriters, {x1 = x2} + {x1 <> x2}.

(* Specifications: *)
Axiom OBJFeq_dec : forall x1 x2 : OBJECT * FILECONT, {x1 = x2} + {x1 <> x2}.
Axiom OBJDeq_dec : forall x1 x2 : OBJECT * DIRCONT, {x1 = x2} + {x1 <> x2}.
Hint Resolve SSCeq_dec OSCeq_dec ACLeq_dec SECMATeq_dec RWeq_dec.