Question

If R1 = {(a,b)|a=b(mod3)} and R2 = {(a,b)|a=b(mod4)} What would be the union of these two?

Answer 1

nvm
I think I got it:
{(a,b) | a-b=4,8,3,6, or 9 (mod 12)}
I think. Not entirely sure

Answer 2

for R1: a-b=3,6,9,...
for R2: a-b=4,8,12,...
the union should be a-b=3,4,6,8,9,12,...
i don't have any idea how to represent these numbers in modulo :(

Answer 3

i don't think mod 12 represents the union of R1 and R2. it represents the intersection of R1 and R2.