Q. The number of non-empty equivalence relations on the set $\{1,2,3\}$ is :
A) 6
B) 5
C) 7
D) 4
Explanation
[Solution by Dr. Abubacker] Equivalence relations correspond to partitions of the set, so the number is the Bell number $B_3=5$. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.