Problem 5f) If {x,y,z} is a superkey, then one of {x},{y}, or {z} must also be a superkey. Problem 5g) If a schema consists entirely of {x,y,z}, and if none of the proper subsets of {x,y,z} are keys, then {x,y,z} must be a key. Problem 5h) If the schema for some relation consists entirely of {x,y,z}, and {y} is the key, then the number of unique x,z> pairs in the relation is equal to the number of y> values