设有关系R和S,试计算:R ∪ S, R - S, R ∩ S, R × S, R |×| S, ∏3,1,2(S), σc>‘5’(R), R |×| S 2<2 R: A B C S: A B C 1 4 6 8 4 6 7 3 2 7 3 2 5 4 9 6 3 5
时间: 2023-03-29 22:00:55 浏览: 252
R ∪ S: {(A,1),(A,4),(A,6),(B,4),(B,6),(B,3),(C,2),(C,4),(C,6),(C,9),(C,5)}
R - S: {(B,3)}
R ∩ S: {(A,4),(C,6)}
R × S: {(A,1),(A,4),(A,6),(B,4),(B,6),(B,3),(C,2),(C,4),(C,6),(C,9),(C,5),(A,8),(B,8),(C,7),(A,7),(B,3),(C,2),(A,5),(B,4),(B,9),(B,5),(C,3),(C,5)}
R |×| S: {(A,1,8),(A,1,7),(A,1,5),(A,4,8),(A,4,7),(A,4,5),(A,6,8),(A,6,7),(A,6,5),(B,4,8),(B,4,7),(B,4,5),(B,6,8),(B,6,7),(B,6,5),(B,3,8),(B,3,7),(B,3,5),(C,2,8),(C,2,7),(C,2,5),(C,4,8),(C,4,7),(C,4,5),(C,6,8),(C,6,7),(C,6,5),(C,9,8),(C,9,7),(C,9,5),(C,5,8),(C,5,7),(C,5,5)}
∏3,1,2(S): {(6,1),(4,1),(3,1),(4,8),(4,7),(4,5),(3,7),(3,2),(5,9)}
σc>‘5’(R): {(B,4),(C,6),(C,9),(C,5)}
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