Propositional Worlds
Smart_Jane &  easy_CS101 GetA_Jane_CS101
Smart_Mike &  easy_Geo101 GetA_Mike_Geo101
Smart_Jane &  easy_Geo101 GetA_Jane_Geo101
Smart_Rick &  easy_CS221 GetA_Rick_C
More transparent representation:
n World = assignment of values to attributes /
truth values to propositional symbols
Knowledge base relates these propositions
Rules of chess (one move) 107 axioms