AD HONOREM SIR ANDREW J. WILES Wiles received the Abel Prize from Crown Prince Haakon of Norway. Wiles ultimately established in a proof both surprising and profound. It is especially appropriate that Wiles’s groundbreaking work on elliptic curves was recognized by the awarding of the Abel Prize, elliptic curves being the natural domains of the elliptic functions introduced n May 24, 2016, Sir Andrew J. Wiles received by Abel. As the citation for the 2016 Abel Prize concludes: the Abel Prize in a ceremony held in the Aula of the University of Oslo in Oslo, Norway. Wiles, “Few results have as rich a mathematical history and as who received the prize from H.R.H. Crown dramatic a proof as Fermat’s Last Theorem.” Prince Haakon at the award ceremony, was The awarding of the Abel Prize was followed by the Othe fourteenth recipient of the 6 million NOK (about Abel Lectures on the next day, May 25. In his lecture, 750,000 USD) prize. A prize honoring the Norwegian Wiles explained how his proof of Fermat’s Last Theorem mathematician Niels Henrik Abel was first proposed by exemplified the movement of number theory from the the world-renowned mathematician Sophus Lie, also from abelian to the nonabelian. Henri Darmon, in his lecture Norway, and initially planned for the one-hundredth an- “Andrew Wiles’s Marvelous Proof,” described Wiles’s work niversary of Abel’s birth in 1902, but the establishment as “a centerpiece of the Langlands program” and ex- of the Abel Prize had to wait another hundred years. The plained its transformative impact, and Manjul Bhargava Abel Prize is administered by the Norwegian Academy of spoke about how Wiles’s work has implications for the Science and Letters. Birch–Swinnerton-Dyer Conjecture. The Abel Prize was awarded to Wiles for “his stunning proof of Fermat’s Last Theorem,” which opened a new era Photo Credits in number theory. The citation of the Abel Committee, Photos are courtesy of Audun Braastad. read by committee chair John Rognes on the occasion of the announcement of the 2016 Abel Prize, recounts the early history of Fermat’s Last Theorem—the assertion that The full text of the citation of the Abel Committee for any given integer 푛 ≥ 3, there are no integer solutions can be found at www.abelprize.no/c54154/binfil/ to 푥푛 + 푦푛 = 푧푛 with 푥푦푧 ≠ 0—and how it was eventually download.php?tid=67039. An expanded version of linked to the then-conjectural modularity of semistable Henri Darmon’s Abel Lecture is included in this issue. elliptic curves and that it was this modularity that Andrew DOI: http://dx.doi.org/10.1090/noti1486 March 2017 Notices of the AMS 197 Interview with Abel Laureate Sir Andrew J. Wiles Martin Raussen and Christian Skau Raussen and Skau : Professor Wiles, please accept our con- gratulations for having been selected as the Abel Prize Laureate for 2016. To be honest, the two of us expected this interview to take place several years ago! You are famed not only among mathematicians but also among the public at large for (and now we cite the Abel Committee): “the stunning proof of Fermat’s Last Theorem, by way of the Modularity Conjecture for elliptic curves, opening a new era in number theory.” This proof goes back to 1994, which means that you had to wait for more than twenty years before it earned you the Abel Prize. Neverthe- less, you are the youngest Abel Prize Laureate so far. After you finished your proof of Fermat’s Last Theorem you had to undergo a deluge of interviews, which makes our task difficult. How on earth are we to come up with questions that you have not answered several times before? Well, we will try our best. Sir Andrew J. Wiles received the Abel Prize from Crown Prince Haakon of Norway. Fermat’s Last Theorem: A Historical Account We have to start at the very beginning, with a cita- this margin is too narrow to contain.” This remark was tion in Latin: “…nullam in infinitum ultra quadratum written in the year 1637 by the French lawyer and amateur potestatem in duos eiusdem nominis fas est dividere,” mathematician Pierre de Fermat [1601–1665] in the mar- which means: “it is impossible to separate any power gin of his copy of Diophantus’ Arithmetica. He certainly higher than the second into two like powers.” In mod- did not expect that it would keep mathematicians, profes- ern mathematical jargon, this can be written: “The sionals, and amateurs alike busy for centuries trying to equation 푥푛 + 푦푛 = 푧푛 has no solution in natural numbers unearth the proof. for 푛 greater that two.” And then it continues: “cuius rei Could you please give us a short account of some of demonstrationem mirabilem sane detexi. Hanc marginis the attempts towards proving Fermat’s Last Theorem up exiguitas non caperet,” which means: “I have discovered a until the time you embarked on your successful journey? truly marvellous proof of this, which Furthermore, why was such a simple-minded question so attractive, and why were attempts to prove it so productive in the development of number theory? Wiles: The first serious attempt to solve it was pre- Martin Raussen is professor of mathematics at Aalborg Univer- sumably by Fermat himself. But, unfortunately, we know sity, Denmark. His e-mail address is [email protected]. nothing about it except for what he explained about his Christian Skau is professor of mathematics at the Norwegian proofs in the specific cases of 푛 = 3 and 푛 = 4.1 That is, University of Science and Technology, Trondheim, Norway. His he showed that you can’t have the sum of two cubes be e-mail address is [email protected]. another cube or the sum of two fourth powers being a For permission to reprint this article, please contact: [email protected]. 1Strictly speaking, Euler was the first to spell out a complete proof DOI: http://dx.doi.org/10.1090/noti1484 in the case 푛 = 3. 198 Notices of the AMS Volume 64, Number 3 fourth power. He did this by a beautiful method, which contradict another well-known conjecture called the Mod- we call infinite descent. It was a new method of proof, or ularity Conjecture. This conjecture had been proposed in at least a new way of presenting proofs in arithmetic. He a weak form by Taniyama [1927–1958] and was refined explained this method to his colleagues in letters, and he by Shimura, but the first real evidence for it came from also wrote about it in his famous margin, which was big André Weil [1906–1998], who made it possible to check enough for some of it at least. After the marginal notes this precise form of the Modularity Conjecture in some were published by Fermat’s son after his father’s death, detail. And a lot of evidence was amassed showing that it lay dormant for a while. Then it was picked up by Euler this should certainly be true. So, at that point, mathe- [1707–1783] and others who tried to find this truly mar- maticians could see that: “Yes, Fermat is going to be true. vellous proof. And they failed. It became quite dramatic Moreover, there has to be a proof of it.” What happened in the mid-nineteenth century—various people thought was that the Modularity Conjecture was a problem that they could solve it. There was a discussion concerning mathematics could not just put to one side and go on for this in the French Academy: Lamé [1795–1870] claiming he was just about to prove it, and Cauchy [1789–1857] another five hundred years. It was a roadblock right in the saying he thought he could too, and so on. middle of modern mathematics. It was a very, very central In fact, it transpired that the German mathematician problem. As for Fermat, you could just leave it aside and Kummer [1810–1893] had already written a paper where forget it almost forever. This Modularity Conjecture you he explained that the fundamental problem was what is could not forget. So, at the point when I heard that Ribet known now as the fundamental theorem of arithmetic. In had done this, I knew that this problem could be solved our normal number system, any number can be factorized and I was going to try. in essentially one way into prime factors. Take a number Raussen and Skau : Concerning speculations about Fer- like 12; it is 2 times 2 times 3. There is no other way of mat’s claimed proof, do you think he had the same idea as breaking it up. But in trying to solve the Fermat problem, Lamé, assuming, wrongly as it turned out, that the cyclo- you actually want to use systems of numbers where this tomic integers have unique factorization? uniqueness does not hold. Every attempt that was made Wiles: No, I don’t think so, though the idea might be to solve the Fermat problem had stalled because of this in there somewhere. It is very hard to understand. André failure of unique factorization. Kummer analyzed this in Weil wrote about this. All the other problems Fermat incredible detail. He came up with the most beautiful considered had to do with curves that were of genus results, and the end product was that he could solve zero or genus one. And suddenly he is writing down a it for many, many cases. For example, for 푛 ≤ 100 he curve that has higher genus.