Functional organization of residual information
Determine the functional organization and role of information retained in the residual subspace after extracting the targeted functional subspaces.
References
An additional open question concerns the role of the residual subspace. As shown in Appendix Section E.10, the residual is not purely nuisance: it can contain or support task-relevant information, but this information appears to be shared or redundant rather than selectively associated with either task. Understanding the functional organization and role of this residual information remains an open direction for future work.
We conjecture that this residual mainly consists of fine pixel detail rather than semantics or layout, consistent with the high-frequency features of pixel models (Figure~\ref{fig:appendix-layer-pca}).