2021-14 Perfectly normal product

Let X, Y be compact spaces. Suppose \(X \times Y\) is perfectly normal, i.e, for every disjoint closed subsets E, F in \(X \times Y\), there exists a continuous function \( f: X \times Y \to [0, 1] \subset \mathbb{R} \) such that \( f^{-1}(0) = E, f^{-1}(1) = F \). Is it true that at least one of X and Y is metrizable?

(added Sep. 11, 8AM: Assume further that \( X \times Y\) is Hausdorff.)

GD Star Rating
loading...
This entry was posted in problem on by .

About Hyungryul

2003.3-2009.8 KAIST, Undergraduate student in Mathematics 2009.8-2014.8 Cornell University, PhD student in Mathematics 2014.9-2017.2 University of Bonn, Postdoc 2017.3-2021.2. KAIST, Assistant Professor 2021.3-Present. KAIST, Associate Professor