I’ve spent the morning reading this preprint: arxiv.org/abs/1805.11556. It has a story behind it. A finance person named @MarcosCarreira does math for pleasure, inspired by @CutTheKnotMath. While playing with a classic problem, he finds something weird in a famous paper about it.
It seems that Marcos discovered an error in that famous paper (by Gilbert and Mosteller) which nobody noticed until now. But I’m not an expert in probability, and it would be great if those of you who are would take a look at Marcos’s paper. It strikes as a neat piece of work.
Marcos uncovered the error by running numerical simulations and finding that his results didn’t quite match the predictions of the classic analysis. Puzzled, he redid the analysis very carefully himself, helped by Mathematica, and found a subtle mistake in the earlier work.
All of this came to my attention thanks to a chance encounter here on Twitter:
https://twitter.com/marcoscarreira/status/1366668573352091656?s=21
I’ve been DM’ing with @MarcosCarreira (who is now a graduate student, after a 20 year career in finance) and he would appreciate any suggestions you have to offer. 
Anyway, I love it when people think for themselves! And I bet if Fred Mosteller were still alive, he would appreciate seeing his pioneering work corrected. The truth is what matters in math.
• • •
Missing some Tweet in this thread? You can try to
force a refresh
