Let X = {−1, 0, 1} and A = ?(x) and define a relation R on A as follows: For all sets s and t in ?(x), s R t ⇔ the sum of the elements in s equals the sum of the elements in t . It is a fact that R is...

Let X = {−1, 0, 1} and A = ?(x) and define a relationR onA as follows:

For all setss andt
in ?(x), s R t  ⇔  the sum of the elements ins equals the sum of the elements int.

It is a fact thatR is an equivalence relation onA. Use set-roster notation to list the distinct equivalence classes ofR. (Enter your answer as a comma-separated list of sets. Enter EMPTY or ∅ for the empty set.)