Solution
= Solution
The original PDF places <complement of a set>[complement] bars on the second $A$ in each parenthesis and on the final $A$. Thus the first parenthesis is the <empty set>, whereas the second is the whole <sample space>. Their <union> with any further <subset> is still the whole space:
$$
\boxed{Y=\Omega}.
$$
The bars are missing from the local OCR, so using its unbarred expression would give the wrong result.