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Use relational algebra to retrieve from the company database the number of employees in research department who do not have any dependent. Turn in your relational algebra expression.

EMPLOYEE Fname Minit John B Franklin T Alicia Jennifer Lname Ssn Bdate Address Sex Salary Super_ssn Dno Smith 123456789 1965-01-09 731 Fondren, Houston, TX M 30000 3334455555 Wong | 333445555 | 1955-12-08 638 Voss, Houston, TX M 40000 888665555 | 5 | Zelaya 999887777 1968-01-19 3321 Castle, Spring, TXF 4 Wallace 9876543211941-06-20 291 Berry, Bellaire, TX F 43000 888665555 4 Narayan 6668844441962-09-15 975 Fire Oak, Humble, TX M 38000 3334455555 English 453453453 1972-07-31 5631 Rice, Houston, TX F 25000 333445555 5 Jabbar 987987987 1969-03-29 980 Dallas, Houston, TXM 25000 987654321 4. Borg 888665555 1937-11-10 450 Stone, Houston, TXM 55000 NULL S K A I V I E Ramesh Joyce Ahmad James DEPARTMENT Dnumber 5 Dname Research Administration Headquarters Mgr_ssn 3 33445555 987654321 888665555 Mgr_start_date 1988-05-22 1995-01-01 1981-06-19 DEPT LOCATIONS Dnumber Dlocation Houston Stafford Bellaire Sugarland 5 Houston PROJECT Dnum Pnumber 1 2 Pname ProductX ProductY Productz Computerization Reorganization Newbenefits Plocation Bellaire Sugarland Houston Stafford ouston Stafford 3 10 20 5 H 30 4 WORKS ON Essn Pno 1234567891 1234567892 6668844443 4534534531 453453453 333445555 12 3334455553 333445555 333445555 999887777 30 999887777 10 987987987 10 987987987 987654321 30 987654321 20 888665555 20 Hours 32.5 7.5 40.0 20.0 20.0 10.0 10.0 10.0 10.0 30.0 10.0 35.0 5.0 20.0 15.0 20 Sex | Dependent_name Alice Theodore F DEPENDENT | Essn 333445555 333445555 333445555 | 987654321 123456789 123456789 123456789 Joy F 30 Bdate Relationship 1986-04-05 Daughter 1983-10-25 Son 1958-05-03 Spouse 1942-02-28 | Spouse 1988-01-04 Son 1988-12-30 Daughter 1967-05-05 Spouse M M Abner Michael Alice Elizabeth F NULL F