#84 - João Batalha and Luís Batalha

**Craig Cannon** (0:00)
Hey, how's it going? This is Craig Cannon, and you're listening to Y Combinator's Podcast. Today's episode is with João Batalha and Luís Batalha, co-founders of Fermat's Library.
Fermat's Library is a platform for annotating papers. Each week, they send out a paper annotated by their community. Some recent ones include Birds and Frogs by Freeman Dyson, and Von Neumann's First Computer Program by Donald Knuth. They've also built a Chrome extension for the archive called Librarian, which allows you to get direct links to references, do BibTeX extraction, and make comments on papers. You can find them at fermatslibrary.com. All right, here we go.
You guys are brothers, right?

**Luís Batalha** (0:37)
Yeah, we are.

**Craig Cannon** (0:38)
Yeah, okay.

**João Batalha** (0:39)
Yeah, he's the older one. I'm two years younger.

**Craig Cannon** (0:41)
Okay, and what made you want to start Fermat's Library?

**João Batalha** (0:46)
So, just for the people that don't know what it is, Fermat is a platform for annotating papers. And so if you want to think about it, you imagine a PDF view in your browser and then you have annotations on the side that support LaTeX and Markdown. And so you can add annotations in parts of papers that you think are particularly tough to understand or you think you could add more content there.
But so it's something that we've done, the four of us that started Fermat, we all have a technical background. And so after college, we kept on reading papers and every once in a while, we had this internal journal club where we would read a paper and present it to the others. So I remember, for instance, presenting a few years back, presenting the Bitcoin paper to Luís and Mika, which don't have a CS background. And so you kind of have to go into, for instance, for the Bitcoin, you might have to go into, okay, what's a hash function? What's a public key encryption? And so we were already doing this.
And we knew that you also have this behavior offline in places like universities. And so we wanted to take that experience and bring it online. And we thought there was a lot of content that you end up producing while you're trying to read a paper, which can be the most dense piece of content that a human can read sometimes, right?
The language can be incredibly Spartan. And sometimes there's a step in some paper that they say, oh, this should be obvious. But then you look at it and it's like, okay, I don't get it.
And so we knew that there was a lot of content there that you end up producing while trying to understand a paper. And we wanted to bring that online.

**Craig Cannon** (2:32)
But Luís, you were in physics before.

**Luís Batalha** (2:35)
I studied physics together with Mika and Joao and Taimo went to MIT. Taimo studied economics and you studied CS.
So a lot of the papers are around physics, math, economics, biology, CS, right?

**João Batalha** (2:52)
Yeah.

**Craig Cannon** (2:52)
Yeah, because that was, you kind of like solved the cold start by just annotating yourself.

**Luís Batalha** (2:57)
Exactly.

**Craig Cannon** (2:57)
Right, and now it's more about getting the author in there.

**Luís Batalha** (3:00)
Exactly, that was the kind of the growth act.

**João Batalha** (3:02)
We start, our first paper was the Bitcoin paper.

**Craig Cannon** (3:05)
Yep, still the most commented, right?

**João Batalha** (3:07)
Yeah, that one has a good number of comments. It has been there for the longest and it was quoted or just there are a bunch of news sites that have pointed back to it. It's like, okay, if you want to read it, go to the annotated version. But we had a few like cool people comment there.

**Luís Batalha** (3:26)
Lawrence Lessig commented on the Bitcoin paper.

**João Batalha** (3:30)
A bunch of people from the Bitcoin community commented there. Yeah, but the larger goal with Fermat is to try to move things in the right direction, meaning move science towards what people call open science. And so that encompasses a number of things from open data, which means just sharing the data that you've used for publishing or whatever research you might be publishing and you want to share that and make that easily accessible to people so that if they want to replicate the results that you got or use it in their own research, they have an easy time doing that. So that's open data. You also have just publishing the code that you used or the algorithms that you've used and making those more easily available to people.
There's also open publishing, which means just publishing in papers that are not behind or in journals that are not behind paywalls. So there's a lot of things that are within open science, all of those, and then there's also... So we want to push things in that direction and also try to build a platform that makes it easier for people to collaborate. And we think there are a lot of things that could be happening nowadays where scientists could be collaborating remotely a lot more than they are, or that's at least the way we think.