pricediscount CUST Y pricediscount CUST Z Y Z pricediscount CUST fivepercent pricediscount CUST tenpercent f a X g Y b p X Y o test relation f a b 3 mary female t' m' v1' ... vk' t' s' t' s' t' m' v' t' m' t' s' t1' ... tn' v' r s room ceiling color a b p X foo bar john believes p X q X some constant d some constant d unequal x person some constant d some function arg1 arg2 arg3 some other function arg4 arg5 arg6 d some constant d some constant d some constant e friend t b x y Steph o unequal unequal x person unequal x person x unequal x person