Coanalytic set

In descriptive set theory, a coanalytic set is a set (typically a subset of a Polish space) that is the complement of an analytic set. In the projective hierarchy, coanalytic sets correspond to $\mathbf {\Pi } _{1}^{1}$ sets.

References

• Kechris, Alexander S. (1995). Classical Descriptive Set Theory. Graduate Texts in Mathematics. Vol. 156. New York: Springer. ISBN 978-0-387-94374-9.