That set has no ring structure. What's the definition of sum and multiplication?
If D is a set, then the power set of D is the set P_D of all the subsets of D.
For example, if D = {1,2,3}, the P_D = { 1, 2, 3, (1,2), (1,3), (2,3), (1,2,3) }
Describe the divisors of zero and invertible elements. I'm supposed to do this for all D, but maybe if someone can show how this works with the above D, i will be able to move forward.
Thanks a lot in advance!