Expander Graphs

Expander experiments produced d-regular ratios very close to one across tested n and d values. For d-regular spectral expanders, d equal to Theta(log n) yields O(log n) worst-case relative distortion with Theta(n log n) edges. The article says theory does not fully explain the near-unit empirical expander ratios. The spectral nuclear-norm refinement suggests low-effective-rank MARL distance matrices can be easier than worst-case metric tables. Random d-regular expander graphs are used as fixed near-linear sparse proxies.