Using the following schema, write the following queries in relational algebra :

Emp(eid, ename, salary) E

Works(eid, did, pct_time) W

Dept(did, dname, budget, manager_eid) D

1. List the employee names of employees who did not work in the R&D department

2. List the employee names of employee who have worked in all departments

3. List the names of managers who manage a department with a budget over $1,000,000

4. List the names of managers who managed more than one department