设 A = { a , b , c } , B = { b , c , d } , C = { d , e , f } , R 1 = { < 1 , 2 > , < 2 , 2 > , < 2 , 3 > , < 3 , 3 > } , R 2 = { < 2 , 2 > , < 2 , 3 > , < 3 , 4 > } 求 设A=\{a,b,c\},B=\{b,c,d\},C=\{d,e,f\},R_1=\{<1,2>,<2,2>,<2,3>,<3,3>\},R_2=\{<2,2>,<2,3>,<3,4>\}求 Let A={ a,b,c},B={ b,c,d},C={ d,e,f},R1={ <1,2>,<2,2>,<2,3>,<3,3>},R2={ <2,2>,<2,3>,<3,4>} Seeking
1. A ∪ B 1.A\cup B 1.A∪B
Find the union of two sets
A ∪ B = { a , b , c , d } A\cup B=\{a,b,c,d\} A∪B={ a,b,c,d}
2. A ⨁ B 2.A\bigoplus B 2.A⨁B
Find the symmetric difference, that is, find the unique elements of the two sets, that is, the union of the two sets minus the intersection of the two sets
A ⨁ B = { a , d } A\bigoplus B=\{a,d\} A⨁B={ a,d}
3. R 1 − 1 3.R_1^{-1} 3.R1−1
Find the relationship R 1 R_1R1The inverse relationship of R 1 R_1R1All the elements in can be reversed
R 1 − 1 = { < 2 , 1 > , < 2 , 2 > , < 3 , 2 > , < 3 , 3 > } R_1^{-1}=\{<2,1>,<2,2>,<3,2>,<3,3>\} R1−1={ <2,1>,<2,2>,<3,2>,<3,3>}
4. R 1 ⋅ R 2 4.R_1\cdot R_2 4.R1⋅R2
Find the intersection of two relations, that is, the common elements in the two relation sets
R 1 ⋅ R 2 = < 2 , 2 > , < 2 , 3 > R_1\cdot R_2=<2,2>,<2,3> R1⋅R2=<2,2>,<2,3>
R 1 restriction on A R_1 restriction on A R1In A on the limit system
R 1 R_1 R1In AAA limitation is the empty set on