# Thread: binary relations 4 parts to this question first one . {

1. ## binary relations 4 parts to this question first one . {

Let S = {0,1,2,3,4} Let R be the binary relation on S such that aRb if and only if a+b=3 and a ≤ 3.
(a) Write this relation down as a subset of the Cartesian product S x S.

Hmm so it reads {a,b} ∈ R

so by substitution we say with a sub set
do we say only{0,3} and {1,2} can be a subset of aRb
eg:- {0,3}{1,2} ⊆ S ?
any help would be good thanks

2. ## Re: binary relations 4 parts to this question first one . {

Not quite. It would be:

$R=\{(0,3),(1,2),(2,1),(3,0)\}$

3. ## Re: binary relations 4 parts to this question first one . {

Thanks SlipEternal obviously missed the last two sub sets