 Okay, I'm talking to Jordan Ellenberg, who just, not just, wrote a book called How Not To Be Wrong, Not To Be Wrong, and yeah, tell us about your book. Well, it's a book I wrote about math, but not so much the kind of math that I do as a researcher. It mostly focuses on actually math that's a lot older. I guess I am imagining people reading it who maybe took math in school but never really were told why they were doing that or what the point of that mathematics was. And I try to make the case of the book that mathematical thinking is part of everything that we do, even if we don't label it as such. I mean, there's a lot of things we do that are mathematical that we don't think of as mathematical. So, that would be a nice example to illustrate that. Do you have something in introduction that we're still... Well, yeah, one example I start the book with, which is a very beautiful one, is about a guy called Abraham Wald, who is a statistician, but he actually starts as a point-set topologist, a very austere, pure mathematician, but he comes to America and gets interested in statistical economics, and he's working at a top secret installation in New York during World War II. Some of the best mathematicians and statisticians in America were sort of like working on war problems. And what happens is that a bunch of generals come to this institution, that statistical research group or SRG, and they say, we've noticed that planes, when they come back from their missions on Germany, they're covered with bullet holes, but there's more bullet holes in some parts of the plane than others. There's like more bullet holes in the fuselage and less on the engines. And they wanted to know if there was some kind of mathematical formula that could tell them how much more armor they had to put on the parts of the plane that were going to hit more. I mean, this is kind of some kind of optimization problem, where you want to allocate the resources you have, the armor you have, to protect the planes most efficiently. And what Wald told them was something that they found quite surprising. He said, you have to put the armor where the bullet holes are not. You have to put it on the engine, not on the fuselage. So this was quite surprising to them, but what Wald explained was that it's not that the Germans couldn't hit their planes on the engines. It's that the planes that got hit on the engines were the ones that were not coming back from Germany. And I like this story because he didn't really give them the kind of answer they expected. He didn't give them that formula. He didn't give them that equation. He didn't give them that number. And the stereotype is that that's what a mathematician does, right? They sort of are asked a question and they provide a numerical answer. What he did is, in fact, I think something much more mathematical than that, that he sort of tried to figure out whether they were asking the right question or whether the question had underlying assumptions in it, and if so, whether those assumptions were correct. In this case, you could say that the assumption is that the planes returning were something like a random sample of planes that had flown missions, which they were decidedly not. So where did you get your sources? I mean, you've been reading about things of this sort for over years, or investigated particularly for the book. Yeah, well, it was a mix. It's funny. I think I started out with some ideas of what I wanted to write about. But as you start to research, I mean, you know, the very nature of math, and this is one reason I was excited to write a book something long. I mean, I've written a lot of articles. But in a book, you can really explore the way all of math touches every other part of math. It's all connected into the surface. So when you start studying one thing right about one story, you find that it connects to another story and another story, and it sort of branches out. So actually, originally, I think I proposed, and the proposal I wrote when I was selling the book in the first place, I had 18 chapters I was going to do. And at some point, I had to call the publisher and say, well, I've written three of the chapters and I have 300 pages. So I said, do you want an 1800 page book five years from now? Or do you more want me just to write five of these? And unsurprisingly, they said, like, no, we want you to write five of these and turn it in on time. So that was certainly why I learned a lot of writing it, actually. And what ends up being the book, tons of stuff that WallStory included that I didn't set out to write about but that I found out about just as I was sort of following trails of math. That's nice. So it must have been quite an interesting experience for you yourself as a mathematician, as a person in general. Yeah, exactly. I mean, I guess maybe one way of saying it is I set out to write about stuff I already knew, which would have been easier. But it turns out it's not that interesting to write about stuff you already know. It's more fun to learn stuff. And so I found myself every time I had an opportunity to sort of follow some trail and learn about some piece of mathematical history, even some piece of mathematics I didn't know anything about. I took it and tried to, to some extent, to try to portray that energy of learning something you're excited about onto the page. Great. So Jordan Nailenberg is a professor of mathematics in the University of Wisconsin, Madison. And he's also written a book that is not a math. Is that right? Yeah, so a long time ago, before I went to grad school, even after college, I went to writing school. I went to a master's program in creative writing. And I wrote a novel called The Grasshopper King, which is, let's just say, a lot fewer people have read it than have read the math book. Well, maybe that will change. And your book has been translated to many languages. As we know, you're going to have a book. What's the word? Yeah, an event, I guess a lot. Today, we are at both the conference at IMPA in Brazil. And this is the event in the Portuguese edition of your book. Exactly. There's actually going to be a Portuguese edition in Portugal as well, which is a separate translation as the Portuguese edition in Brazil. This is the first translation to come out. And the next one will be the Italian version, which is coming out, I think, July 16th. Let's see if I can say the title. Inumeri non spaleo mai, which means numbers don't lie. That's the Italian version. Numbers never make mistakes. Oh, OK, OK. OK, sounds good. So what's up on your plate? Do you have more projects? Well, now I'm really trying to finish all the theorems that I didn't finish while I was writing this 500-page book. So I'm cleaning my plate. And you know, Fernando, you and I are here at this conference at IMPA in Brazil, learning about number theory and physics. And it's all pretty awesome. OK, well, thanks very much, Jordan. And look best of luck for your book and so on. And I'll keep you posted. Maybe I'll come contact you again for something else. Awesome, thanks, Fernando. Ciao.