Prolog

I want to figure out, what relationship between X and Y does the query

$?-$ parent$($Z$,$X$),$ parent$($Z$,$Y$),$ X $\backslash =$ Y$.$ imply?

Hints are that

that $\backslash =$ means $$not equal to$,$ i$.$e$.,$X is not equal to Y$.$

that both of these queries of will produce duplicates $$ that is okay.

After that, how would I write a rule in terms of just X and Y for that query?