# How To Write this set

1. Dec 7, 2009

### anonymous007

Hi, I was just wondering, if I have a set (denoted by A)of natural numbers, 1,2,3,4,5,6,7,8,9,10 and each element(1,2,3,4,5,6,7,8,9,10) in the set is denoted by a,b,c,d,e,f,g,h,i,j

and set B is the natural numbers 2 and 3

How would I say that if an element in set B is a factor of an elemetn in set A, then take that element in A( which B is a factor of) and and place it into a set C

for example, since the elemetents 2,3,4,6,9,10 in set A are multiples of the elements in set B
then set C is the elements 2,3,4,6,9,10

2. Dec 8, 2009

### grief

C={a in A : $$\exists$$ b in B such that b|a}. Is that what you meant?