Almost eight years ago I launched Fanography. It has just received its biggest technical overhaul since then: fanography.info is now a static website, generated with Hugo and served from GitHub Pages.

From Flask to Hugo

Before, Fanography was a Flask application: a little Python server that assembled each page on the fly from the underlying classification data. That worked well, but it meant there was always a server that needed to keep running, be kept up to date, and be paid for in one way or another. So I rebuilt it from scratch with Hugo:

The old Flask application has been retired. As with moving my own website to Hugo, the migration should be invisible to visitors—please let me know if something broke!

New information on Fanography

Whilst I was busy with Fanography, I decided to add a bit of data that I've wanted to be there for a long time.

The Mori–Mukai determinant
Each entry page now displays the Mori–Mukai determinant $d(X)$, and it is included for all 105 families. I wrote about this invariant, and how I computed it for every family, in a separate blogpost.
Holomorphic Poisson structures
There is a new card recording the holomorphic Poisson structures on $X$, that is, the global sections $\pi$ of $\wedge^2\mathrm{T}_X$ for which the Schouten–Nijenhuis bracket with itself vanishes, i.e., $[\pi,\pi]_{\mathrm{NS}}=0$. For Fano 3-folds of Picard rank 1 these were classified by Loray–Pereira–Touzet, and the card lists the irreducible components of $\mathbb{P}\mathrm{H}^0(X,\wedge^2\mathrm{T}_X)$ together with their dimensions. For higher Picard rank the classification is, as far as I know, still open. This sounds like a fun challenge!

Other improvements

A small quality-of-life improvement: you can now use the left and right arrow keys to move between consecutive families, which makes browsing the classification in order much more pleasant.

A handful of smaller additions came along for the ride:

  • several rank-1 Fano 3-folds are now referred to by name;
  • del Pezzo surface pages show the number of exceptional lines, and their polyvector parallelogram.

Maybe more updates to come soon!

Oh, and hyperkaehler.info is now also a static website! But that one didn't get any improvements, so no separate blogpost.