It happens surprisingly often that somebody tells me that I don’t travel, that I don’t fly. Alternatively, people who see me somewhere often say, “Now that you’re traveling again.” I never know what to say, because I do travel and I do fly.

It’s true that I used to travel much more. I did a lot of traveling. And when I say a lot, I mean a lot. Okay, many people, mostly Americans, travel more than I ever have, but I’ve seen a lot of airplanes from the inside. Then, at some point, I started doing it much less. It’s not entirely clear why, but I’m sure COVID had something to do with it. It was during COVID that I first understood how nice it is to work from home. How nice it is to take breaks—quite a few breaks, actually—scratching cat bellies. How nice it is to nap in a proper bed. How nice it is to work in house shoes and comfy pants. I guess many people discovered these things at the same time, but most of them have been slowly forced back into their office schedules. Not me. One of the many ways I’m privileged is that nobody really cares if I go to the office or not. Okay, I suppose some people would prefer if I were a more assiduous attendee of seminars and such, and I see their point. On the other hand, one can only fight so much against one’s nature, and as somebody said at some point, I have an extraordinary talent for skipping talks. Anyways, COVID showed me a world of new opportunities—work in the bathtub, anyone?—and I embraced them. Now, I travel, but when I do, I miss my bathtub and those cat bellies, and I guess that sometimes makes me prefer skipping the next conference.

Besides COVID, there was also the flu. As I wrote here, it was the flu that made me a vegetarian: it was long, I had time to learn about climate change, and I understood that things I was doing were actually pretty damaging. I decided it was a good idea to do less of them, even if the only realistic goal is to buy some future goodwill from my daughter. Anyways, besides becoming a vegetarian, I also decided to limit how much I fly. If I’m not mistaken, since 2019, I’ve taken five one-way flights. As you see, I still fly, but I just try to avoid it as much as possible. I promised the being that when she can order food in Chinese, I’ll take her to China. Evidently, we’ll fly. Similarly, I’m hoping to go to Toronto—by plane—for something like two months next year. There are places one has to fly to. I just think it has to be worth it, that one should consider the environmental damage as one considers the price, and that if at all possible, one should take trains, buses, and ferries instead. Trips to Madrid, Ravenna, or Dublin become pretty long and tiring, but I guess tiredness is the currency of future goodwill. In any case, environmental concern and tiredness put a brake on how much I travel. But I travel.

Now, to do math, I need to talk to people. I can read the newspaper alone, but to think and have ideas, I have to talk. Naively, one might think this would be simpler at the office than at home. However, I don’t see any difference. I mean, when I go to the office, I sometimes go tell somebody something I’ve learned or am thinking. This never happens in the other direction. Never. I’m not sure why, but it doesn’t. It might well have something to do with me, but my interpretation is that everybody is just too busy with their own things to go around wasting time chatting. In any case, independently of whether I go to the office or not, when I talk math with people—and it happens quite often: I did it for almost four hours today—it always ends up taking place via video conference. Video conferences aren’t the same as person-to-person conversations, but I actually like that medium quite a bit. What I don’t like doing is writing things on my tablet for everybody to see. Probably because I don’t know how to do it well and because my horrible handwriting becomes even worse. An advantage of going to the office is that I can just point the camera at the blackboard. My handwriting there isn’t better, but I’ve grown to accept it. One can’t be universally talented. I guess that God, nature, or whoever did that, just decided I was already blessed enough with the talent to skip talks and that proper handwriting would remain beyond me.

Anyways, not being able to write on a tablet disqualifies me from giving online talks. I’ve tried it, and it was horrible. I don’t do that. Now, talks have to be given. At the end of the day, since few people actually read what one writes, talks are the way people learn about one’s new groundbreaking findings on the nature of the gender of angels. Luckily, I’ve been blessed with coauthors who like to travel, and I suppose they’ve given talks alright about whatever we did. From my point of view—and I gather also from theirs—that worked well. In any case, I think that in the past, I already did my fair share of tiring trips where you go give a talk in front of a bunch of people who sit there politely but who evidently don’t care at all about what you’re saying. Tiring trips where you invariably wonder why the fuck you went. Nowadays, it’s much less likely that I’ll agree to go to one of those circuses, leaving behind the bellies and the bathtub. I travel, also for math, but I only want to travel if it makes sense to me—basically, if I’ll stay long enough and get enough conversation to make it worth it.

Other than leisure trips and short trips to Paris, in the first six months of this year, I’ll have spent at least a week in Leipzig, Helsinki, Dublin, and maybe Bonn. I don’t know about you, but I call that traveling. And I’m flying to Helsinki because the alternative takes three days each way—and that’s only if the Bundesbahn cooperates, which isn’t a given. Anyways, it’s true that this is more travel than I’ve been recently doing. So, why? Well, I don’t know. Maybe a fluke. Maybe I just feel like it. But I guess it also plays a role that I tend to get tired of the math things I do, and that what seems to happen in these cases is that the butterfly—that’s me—just starts flapping around to find some other sufficiently low-hanging fruit. Low-hanging fruit that comes with some new collaborators. This is what’s happened every time my priorities have shifted from proving the 72nd variation of Lemma 3.7 to looking for alternatives to proving it for the 73rd time. Escaping Lemma 3.7 might be one of the reasons why, right now, I feel more like traveling. But for whatever reason, yes, I travel. And I fly. I just ration the flights and try to make sure the trip is worth it.