Minimal dimension for translational aperiodic monotiles
Determine the smallest integer dimension d for which there exists an aperiodic monotile in R^d that tiles by translations alone, as guaranteed to exist in some sufficiently high dimension by Greenfeld and Tao.
References
In recent work, Rachel Greenfeld and Terence Tao proved that in a sufficiently high number of dimensions---high enough that the exact number is not known---there exist aperiodic monotiles that tile by translation alone.
                — The Path to Aperiodic Monotiles
                
                (2509.12216 - Kaplan, 2 Sep 2025) in Section discussing higher-dimensional aperiodicity (end of "Aperiodicity")