cartesian-product

Let $$X,. Y, Z$$ be sets of sizes $$x, y$$ and $$z$$ respectively. Let $$W = X x Y$$ and $$E$$ be the set of all subjects of $$W$$. The number of functions from $$Z$$ to $$E$$ is

A relational database contains two table student and department in which student table has columns roll_no, name and dept_id and department table has columns dept_id and detp_name...

Given relations r( w, x ) and s( y, z ), the result of select distinct w,x from r, s; is guaranteed to be same as r, provided

Let $${\rm A}$$ be a finite set of size $$n$$. The number of elements in the power set of $${\rm A} \times {\rm A}$$ is