Hi, I'm
Fabian.

I model the NYC Subway Challenge as a time-expanded routing problem over the real MTA schedule. My current best validated route visits all 472 stations in 24:24:30.

Fix only your home airport, list the cities you want to visit, and let a time-expanded traveling-salesman model pick the cheapest order and dates. We use it to price two bucket-list trips: the world's 10 most-visited cities and the New 7 Wonders.

In honor of Scripps 2026, we analyze every one of the almost 3,000 honeycombs in the history of the NYT's Spelling Bee — and how they fare against all 7-letter words from Collins Scrabble Words. We conclude with a detour to another language, German.

This post is about two topics: first, as the title suggests, it is about studying the graph behind the Mathematics Genealogy Project and its many interesting — and, at times, surprising — properties (the "what"). But maybe more importantly, second, it is about "how" this post was written.

We analyze a Kaggle dataset with 10 million Glassdoor reviews to answer the question, "are employees happier at small companies?"