... - If p~, then p is a formula. - If p and q are formulas, then (-p), (p v q) are formulas. - If m is a unary temporal operator and p is a formula, then (m p) is a formula. - If m is a binary ... any of the stronger forms of future possibility can be derived it would be desirable to provide information to that effect. For example, if a student is not registered for a course and has ... might arise. For the question, "Could I have registered for CSEII0 last semester?", we access the state specified by last semester, and from that state description, reason forward regarding...