Existence of good compactifications for arbitrary pairs
Determine whether every pair (X, Y) of complex algebraic varieties with X \ Y smooth admits a good compactification (\overline{X}, \overline{Y}) in the sense of Definition "good compactification": \overline{X} is a compactification of X, \overline{Y} is the Zariski closure of Y in \overline{X}, \overline{X} \setminus \overline{Y} is smooth, and the triple (\overline{X}, \overline{Y}, Z) with Z = \overline{X} \setminus X is locally of product type.
References
We do not know whether every pair $(X,Y)$ admits a good compactification.
                — Positive geometries and canonical forms via mixed Hodge theory
                
                (2501.03202 - Brown et al., 6 Jan 2025) in Section "Genus and compactification", after Definition "Good compactification"