[petergeoghegan]

The paper says 83x, and even makes stronger claims that are fairly unqualified:

In short, the experimental achievements of the PGM-index are: (i) better space occupancy than the FITing-tree by up to 75% and than the CSS-tree by a factor 83×, with the same or better query time; (ii) uniform improvement of the performance of RMI in terms of query time and space occupancy, and 15× faster construction, while requiring no hyperparameter tuning; (iii) better query and update time than a B+-tree by up to 71% in various dynamic workloads while reducing its space occupancy by four orders of magnitude (from gigabytes to few megabytes).

I wonder why it was just four orders of magnitude, though. Why not six or twelve?

[inciampati]

Have you examined the results presented in section 7? They take pains to qualify these claims.

If you are curious, the authors have provided completely reproducible experiments.

[petergeoghegan]

I didn't say that these specific claims are simply false. Just that they sure seem to hint at extraordinary improvements in a broad range of cases. The website itself also seems to me to be suggestive in just the same way, only much more so.

I myself don't think that that amounts to taking pains to qualify their claims. Other people will have to make their own minds up about whether or not that's the case.