Functions Question 478

Question: Total number of equivalence relations defined in the set $ S={a,b,c} $ is:

Options:

A) 5

B) 3!

C) $ 2^{3} $

D) $ 3^{3} $

Show Answer

Answer:

Correct Answer: A

Solution:

[a] The smallest equivalence relation is the identity relation $ R_1={(a,a),(b,b),(c,c) $ Then two ordered pairs of two distinct elements can be added to give three more equivalence relations $ R_2={(a,a),(b,b),(c,c),(a,b),(b,a)} $ Similarly $ R_3 $ and $ R_4. $ finally the largest equivalence relation i.e., the universal relation