Prove that non$-$recursive Datalog without negation and relational algebra with selection, projection, and Cartesian product operators express the same set of queries. In this question, we consider only the non$-$recursive Datalog without negation queries with a single rule. We also consider only the relational algebra queries that produce non$-$empty answers over at least one database instance. Theorem $4\mathrm{.}4\mathrm{.}8$ in Alice Book provides a summary of this proof. You should

complete this summary and submit your proof.