Syntax Basic element:random variable Similar to propositional logic:possible worlds defined by assignment of values to random variables. Boolean random variables e.g.,Cavity(do I have a cavity?) Discrete random variables e.g.,Weather is one of <sunny,rainy,cloudy,snow Domain values must be exhaustive and mutually exclusive Elementary proposition constructed by assignment of a value to a random variable:e.g.,Weather sunny,Cavity false (abbreviated as -cavity) Complex propositions formed from elementary propositions and standard Syntax • Basic element: random variable • Similar to propositional logic: possible worlds defined by assignment of values to random variables. • Boolean random variables • e.g., Cavity (do I have a cavity?) • Discrete random variables • e.g., Weather is one of <sunny,rainy,cloudy,snow> • Domain values must be exhaustive and mutually exclusive • Elementary proposition constructed by assignment of a value to a • random variable: e.g., Weather = sunny, Cavity = false • (abbreviated as cavity) • Complex propositions formed from elementary propositions and standard logical connectives e.g., Weather = sunny  Cavity = false