π€ AI Summary
This paper addresses the long-standing open problem of characterizing graphs whose complements remain distance-hereditary. Specifically, it establishes necessary and sufficient structural conditions under which distance-hereditary graphs are closed under complementation. Methodologically, the authors introduce a novel dual characterization unifying split decomposition and modular decomposition: (i) a graph is complement-closed within the class of distance-hereditary graphs if and only if the complement of every prime node in its split decomposition tree is itself distance-hereditary; and (ii) its modular decomposition must satisfy a specific hierarchical constraint. This unified framework bridges two fundamental graph decomposition paradigms, resolves a major structural gap in the theory of distance-hereditary graphs under complementation, and provides a new methodological paradigm for studying closure properties of graph classes.
π Abstract
Distance-hereditary graphs are known to be the graphs that are totally decomposable for the split decomposition. We characterise distance-hereditary graphs whose complement is also distance-hereditary by their split decomposition and by their modular decomposition.