4. (6 points) You are modeling a computer system which has three error flags: the COM flag is set to on when the computer is out of memory; the DEO flag is set to on when a disk error occurs; the NET flag is set to on when network connectivity is unreliable. Are the following system specifications consistent? If the computer is out of memory, then network connectivity is unreliable. No disk errors can ocecur when the computer is out of memory. For full credit, describe your model by associating propositional variables with each of your basic propositions are not consistent