Thread: Equivalence Relation question

Let A = NxN, and define a relation R on A by (a,b)R(c,d) iff ab = cd.

I already proved that this is a relation.
But the question also asks to find the equivalence class E(9,2), and find an equivalence class with exactly 2 elements, one with 3 elements and one with 4 elements.
Im not sure how to do that with this question, or what that last part even means.

any help?

Originally Posted by p00ndawg

Let A = NxN, and define a relation R on A by (a,b)R(c,d) iff ab = cd.
But the question also asks to find the equivalence class E(9,2), and find an equivalence class with exactly 2 elements, one with 3 elements and one with 4 elements.

Now you finish.

just to make sure im understanding,

E(1, 4)= {3 elements} ??

Originally Posted by p00ndawg

just to make sure im understanding,

E(1, 4)= {3 elements} ??

What are the elements?

Originally Posted by plato

what are the elements?

(1,4), (4,1) (2,2)?

Originally Posted by p00ndawg

(1,4), (4,1) (2,2)?

Exactly.