EPub.discount <- EOrg.preferred ^ EPub.student
EOrg.preferred <- ACM.member
EOrg.preferred <- IEEE.member
ACM.member <- Alice
ACM.member <- Cindy
ACM.member <- Brian
EPub.student <- EPub.university.stuId
EPub.university <- ABU.accredited
ABU.accredited <- StateU
StateU.stuId <- Alice
StateU.stuId <- Cindy