# Thread: How to express in set builder notation?

1. ## How to express in set builder notation?

I have two relations,

R1: { (copy1, member1), (copy2, member1), (copy3, member2), (copy4, member2) }
R2: { (copy1, 3), (copy2, 5), (copy3, 6), (copy4, 2) }

Note: In both R1 and R2, copy# should not repeat.

I want a set of all copies against "member1" whom due date is less than x, where x belongs to Natural numbers.

2. ## Re: How to express in set builder notation?

Originally Posted by Osman
I have two relations,

R1: { (copy1, member1), (copy2, member1), (copy3, member2), (copy4, member2) }
R2: { (copy1, 3), (copy2, 5), (copy3, 6), (copy4, 2) }
Note: In both R1 and R2, copy# should not repeat.
I want a set of all copies against "member1" whom due date is less than x, where x belongs to Natural numbers.
Should it be $\displaystyle R_2=\{(c_1,m_3),(c_2,m_5),(c_3,m_6),(c_4,m_2)\}~?$

But you have written $\displaystyle R_2=\{(c_1,3),(c_2,5),(c_3,6),(c_4,2)\}$
That is different than the format from $\displaystyle R_1$.