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Suppose that R is the following relation on the set A 11,2,3,4)

R = {(1,1), (2,2), (3,3), (4,4), (1,3), (3,1), (2,4), (4,2))
Then which of the following is true about R²?
(Hint: there is no need to determine R2 explicitly. You just need to recognize some of the properties of R and apply a general principle.)
A. equal. R²=R
B. subset. R²⊆R
C. superset. R²⊇R
D. not comparable.

1 Answer

2 votes

Final answer:

Given the properties of the relation R, including identity and symmetric pairs, we can deduce that R² will contain all the pairs in R and is therefore at least a superset of R.

Step-by-step explanation:

The relation R on set A is defined as R = {(1,1), (2,2), (3,3), (4,4), (1,3), (3,1), (2,4), (4,2)}. To determine the nature of R² without explicitly calculating it, we recognize that R includes all of the identity pairs (x, x) for each element x in the set A, which is a characteristic of the identity relation. Furthermore, for each non-identity pair (x, y) in R, the inverse pair (y, x) is also in R, suggesting reflexivity and symmetry.

Considering these properties, R², which is the composition of R with itself, would contain at least all of the same pairs as R since composing any identity pair with itself yields the same pair and composing a pair and its inverse will yield the identity pairs. Therefore, without explicitly calculating R², we can deduce that R² is at least a superset of R, if not equal.

Thus, the correct answer is C. superset. R²≥R.

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