What do you think?
I read a joke recently. A man with a multiple personality disorder who found himself on an uninhabited island soon found a lot of friends.
I came across an interesting question and am curious on how to answer it.
What sort of relation is friendship? Is it necessarily reflexive, symmetric, anti-symmetric, or transitive? Can the friendship relation among a finite group of people induce a partial order, such as a set inclusion?
This chapter discusses relation as a mathematical term. For sets A, B, any subset of A x B is called a (binary) relation from A to B. Any subset of A x A is called a (binary) relation on A.
I have no idea how to apply this to the question.