cs.DM — Discrete Mathematics
Fractional DAG treewidth controls DAG treewidth: profile reorientation and VC-dimension rounding
For a nonempty finite graph, let be its fractional DAG treewidth, maximized over all acyclic orientations. Its DAG treewidth is at most . This answers the boundedness question of Bressan, Lanzinger, and Roth. Reorienting the graph converts shattered source profiles into projective-plane obstructions, which bound their VC dimension by . Classical epsilon-net rounding then converts fractional bag covers to integral ones without changing the decomposition.
Primarily AI-generated textHuman understanding: some partsDAG treewidthVC dimensionepsilon netsfractional hypertreewidthgraph homomorphisms