Flag-accuracy characterization of free connected subgraph arrangements

Prove that a connected subgraph arrangement is free if and only if it is flag-accurate.

Background

Flag-accuracy strengthens the accuracy property by requiring the relevant flats to form a flag. The paper establishes flag-accuracy for several families and reports computational evidence for additional almost-path cases. These results motivate the conjectured equivalence between freeness and flag-accuracy throughout the class of connected subgraph arrangements.