Homework Statement
Prove or disprove and salvage if possible: for [a], [b] ∈ Zn for a positive integer n, if [a]·[b]=[0], then either [a]=[0] or [b]=[0].
The Attempt at a Solution
I've managed to disprove the statement:
Let n=6,[a]=3,and[b]=[4]. The[a]·[b]=[ab]=[3·4]=[12]...