##### Exercise1

Yes/No. For each of the following, write Y if the object described is a well-defined set; otherwise, write N. You do NOT need to provide explanations or show work for this problem.

\(\{z \in \C \,:\, |z|=1\}\)

\(\{\epsilon \in \R^+\,:\, \epsilon \mbox{ is sufficiently small} \}\)

\(\{q\in \Q \,:\, q \mbox{ can be written with denominator } 4\}\)

\(\{n \in \Z\,:\, n^2 \lt 0\}\)