- #1
jwxie
- 281
- 0
This is an example from the book.
For B = {1,2}, let A = P(B) = {empty, {1}, {2}, {1,2} }
The following is an example of relation on A:
R = {
(emp,emp),
(emp, {1})
(emp, {2}),
(emp, {1,2}) ,
({1},{1}),
({1}, {1,2}) ,
({2},{2}),
({2}, {1,2},
({1,2},{1,2}),
}
My question is, what happen to ({1}, emp), ({2}, {1}.. i see the trend that it is skipping everything before the current relation. Why?
Like A X B
let A = {1,2} and B = {2,3,4}
We will have 1,2 1,3 1,4 2,2, 2,3 2,4
For B = {1,2}, let A = P(B) = {empty, {1}, {2}, {1,2} }
The following is an example of relation on A:
R = {
(emp,emp),
(emp, {1})
(emp, {2}),
(emp, {1,2}) ,
({1},{1}),
({1}, {1,2}) ,
({2},{2}),
({2}, {1,2},
({1,2},{1,2}),
}
My question is, what happen to ({1}, emp), ({2}, {1}.. i see the trend that it is skipping everything before the current relation. Why?
Like A X B
let A = {1,2} and B = {2,3,4}
We will have 1,2 1,3 1,4 2,2, 2,3 2,4