arxivcs.LG2026-07-17
Hierarchical Domain Generalization
Chenxiao Yang, Zhiyuan Li, Shai Ben-David, Nathan Srebro
We study hierarchical domain generalization as a problem of extrapolation from finite observed regions to an entire instance space, replacing i.i.d. sampling with arbitrary domain hierarchies. We show that the central obstruction is not only the complexity of the hypothesis class…