I wasn’t going to write about this. I was going to keep it to myself. But then Klaus Tschira, the chairperson of the HLF Foundation, mentioned it in his welcoming speech, and he didn’t mince words.

“Some may feel there are not many mathematicians present,” Tschira said. “Personally, I feel very sorry about this.” The number of living laureates of the Fields and Abel prizes (the two math prizes represented at this meeting) is roughly equal to the number of Turing and Nevanlinna laureates (the two computer science prizes). Every living laureate was invited. And yet, by my rough count, 9 of the 39 laureates who have come to Heidelberg are mathematicians. In other words, the attendance rate among computer scientists was *three times* that of the mathematicians who were invited.

The disproportion, Tschira said, is “even more deplorable because the jury [which evaluated the applications of the young researchers who applied to come] admitted an equal number of young researchers in the two fields.” That’s 100 young computer scientists and 100 young mathematicians. What message will the 100 young mathematicians get from this conference? That the leaders in their field do not care about mentoring the next generation? That they do not care to attend a meeting that is half devoted to computer science?

Tschira mentioned that there had been a couple of late cancellations, for medical reasons, who happened to be mathematicians. That is unfortunate, but it still does not truly explain the disproportion.

I asked Ingrid Daubechies, the president of the International Mathematics Union, and Ragni Piene, the chair of the Abel Prize Committee, what they thought about the problem. Daubechies thought that the timing of the conference may have been inconvenient for mathematicians. The dates were chosen so that the attendees could enjoy the “altweiber Sommer” (Indian summer) weather in Heidelberg. But unfortunately, late September is also when universities are starting their classes. Perhaps more of the mathematical laureates had teaching duties than computer science laureates did.

Piene was skeptical of this explanation in general, as am I. She does know personally one Fields medalist (and member of the Abel prize committee) who is so committed to his teaching that he couldn’t attend. Though I have nothing but praise for this individual, I can’t believe that mathematicians as a group are more likely (by a three-to-one margin?) to have teaching duties or to be more committed to them than computer scientists.

Do I know why there are so few prominent mathematicians here? No. Am I surprised? No. I have some theories, only one of which I will mention here.

From a professional lifetime in math and around math, I have observed that when it comes to interdisciplinary work, a lot of mathematicians talk the talk but they don’t walk the walk. This is especially true of pure mathematicians. When funding time comes around, they will tell you that many discoveries in pure mathematics have eventually led to valuable applications. I have no argument with that. But are those mathematicians *personally* interested in seeing their work applied, to go the extra mile and work with other scientists and find out what those scientists’ *real* mathematical needs are?

Some of them are, and do. But not enough. It’s not part of their culture. So when they are offered an opportunity to come to a meeting like this, a forum that may not help them on their specific research agendas but offers a huge potential gain for their discipline, what happens? They put up a “Not interested” sign.

As Daubechies pointed out, it is a big opportunity missed. “For example, there is so much interaction between mathematics and machine learning,” she told me. “People from geometry, topology, a lot of different fields are working on ways to find structure in large data sets.” This conference would have been an ideal chance for mathematicians to forge even stronger connections with computer science. The “big data” problem isn’t going away. It’s one of the major scientific problems of the day. This was a chance for mathematicians to be relevant… not potentially, in some distant future, but *now*.

Sorry. Not interested.

Fortunately, some people *are* interested: the 100 young mathematicians at the forum, who (based on my totally unscientific sample at the reception this evening) are not so scared of crossing disciplinary borders, and are eager to find out what problems their computer science colleagues might need some help with.

There is other bright side to look at — a side that is impossible to ignore, in fact. I’m referring to the fact that nine Fields and Abel medalists *did* take the trouble to come to Heidelberg. Any meeting that can claim among its attendees Sir Michael Atiyah, Gerd Faltings, Curtis McMullen, Steven Smale, Andre Szemeredi, Srinivasa Varadhan, Cedric Villani, Vladimir Voevodsky, and Efim Zelmanov is a *great* meeting. Or to use language that is more common for the younger generation (I think), it is *epic*. So I will say nothing more about the people who aren’t here, and I will look forward to writing for the rest of this week about the people who are here.