Suppose the system enforces both BLP and Biba properties. For BLP which means read down/write up only and for Biba it means read up/write down only. Suppose also that two models use identical levels for both security and integrity SL = security clearance for level L = integrity clearance for level L SC = security category set for cat. C = integrity category set for cat C Prove that in this system subject can only read and write at his own level.