numerative ombinatorics

A pplications Enumerative Combinatorics and Applications ECA 2:1 (2022) Interview #S3I3 ecajournal.haifa.ac.il

Interview with Greta Panova Toufik Mansour

Greta Panova completed her undergraduate studies at the Mas- sachusetts Institute of Technology, where she obtained two bachelor’s degrees: in Mathematics and in Electrical Science and Engineering. She completed her master’s studies at the University of California, Berkeley. She obtained a Ph.D. from Harvard University in 2011, under the direction of Richard Stanley. She currently holds the position of Associate Pro- fessor (with tenure) at the University of Southern California. From 2011 up to 2014 she was a Simons Postdoctoral Fellow at the University of California Los Angeles. During the period 2014-2018, she was an Assistant Professor, promoted to Asso- ciate (with tenure), at the University of Pennsylvania. During the period 2017-2018, she was a Von Neumann Fellow at the Institute for Advanced Studies in Princeton. Professor Panova has given numerous talks at many conferences and seminars. We list here some of her ple- nary talks: Triangle Lectures in Combinatorics, Greensboro, NC. (2016); Formal Power Series and Algebraic Combinatorics, London, UK (2017); Algebraic and Enumerative Combinatorics Conference, Okayama, Japan (2018). Greta Panova received many prizes and awards with the most recent one, the IMI prize for 2020, the prize awarded by the Institute of Mathematics and Informatics of the Bulgarian Academy of Sciences. She is currently one of the Editors-in-chief of The Electronic Journal of Combinatorics.

Mansour: Professor Panova, first of all, we and the problems solved with external tools, would like to thank you for accepting this in- all of which make this area very diverse, well- terview. Would you tell us broadly what com- connected to others, and its boundaries hard binatorics is? to define. Panova: Thank you for inviting me, it is an Mansour: What do you think about the de- honor to be interviewed. velopment of the relations between combina- Combinatorics is generally speaking the torics and the rest of mathematics? area of mathematics that studies discrete ob- Panova: Combinatorics is centrally posi- jects without too much underlying structure tioned within mathematics. Combinatorial ob- and relations, which is what distinguishes it jects, in their simple structure, could manifest from algebra and number theory. Combina- in external problems and then combinatorial torics itself has many subareas which do not methods become powerful tools. For exam- necessarily interact much with each other – ple, at the heart of algebraic combinatorics lie graph theory, enumerative, analytic, algebraic enumerative techniques and symmetric func- combinatorics can all be very different and tions, which directly apply in representation even within themselves divided. Combina- theory to understand module dimensions and torics has both its methods and its problems, structure through multiplicities. We can see the methods could be applied to other fields, such connections everywhere – in probability The authors: Released under the CC BY-ND license (International 4.0), Published: April 2, 2021 Toufik Mansour is a professor of mathematics at the University of Haifa, Israel. His email address is [email protected] Interview with Greta Panova and statistical mechanics, algebra and number combinatorial quantities through the prism of theory, algebraic geometry, topology... Com- complexity classes and explain formally why binatorics goes beyond math, as it is among we do not have “nice” formulas, or even “com- the main tools in theoretical computer science, binatorial interpretations” sometimes. game theory, etc. Moreover, the interaction is Mansour: We would like to ask you about two-way, as algebraic and probabilistic meth- your formative years. What were your early ods play an important role and seemingly sim- experiences with mathematics? Did that hap- ple combinatorial problems have been solved pen under the influence of your family or some with the powerful machinery of other fields. other people? For example, algebraic geometry has been used Panova: My parents are both very far from to prove the unimodality of combinatorial se- mathematics, although as a law professor (my quences as in the works of Richard Stanley1 mother) and as a medical doctor (my father), in the 80s and June Huh2 much more recently; education in my family has always been highly Haiman’s3 proof of the n! conjecture is another valued. My mother was steering me to study example. languages early on, which I greatly resisted, Mansour: What have been some of the main and instead spent my time at home quietly goals of your research? drawing and disassembling things out of cu- Panova: I try to find connections with other riosity and desire to build something else out fields, expand the application of combinato- of their parts resulting in inevitable destruc- rial methods there and also solve combinato- tion and sometimes injury. My memories from rial problems using external methods. One elementary school are quite blank in the cloud direction is the study of interacting particle of my peer’s hostility. When I was in 4th grade systems, dimer models in statistical mechanics my mother won a Humboldt fellowship and we which often benefit from the use of symmetric spent one year in Germany, where I started functions; and in the opposite direction proba- exhibiting some math skills recognized by the bilistic methods can explain the asymptotics of teachers. Back in Bulgaria, I went to a better combinatorial quantities. Another direction is middle school, and after 7th grade I was ad- computational complexity in theoretical com- mitted to and enrolled in the National High- puter science, where a good understanding of School of Mathematics and Sciences, defeating structure constants in algebraic combinatorics my mother’s push to go to a language high- (e.g. the Kronecker and plethysm coefficients) school by failing the literature entrance exam. could lead to computational lower bounds. In high school, I started going to math compe- This is the basis of geometric complexity the- titions, which turned out to be actually fun. I ory (GCT) which aims to distinguish the al- ultimately made it to the national team for the gebraic version of P vs NP, the VP vs VNP IMO, where I got gold and two silver medals. problem, by exploiting the symmetries of the These were my entrance ticket to MIT and the universal polynomials – the permanent and de- rest is in my CV. I must add though, that de- terminant. Unfortunately, our work on Kro- spite all the math I was doing in high school, necker and plethysm coefficients and disprove during my entire childhood I wanted to become of the weak GCT conjecture revealed that the an architect and that is what I started with at stepping stones in GCT are higher than we MIT. can currently reach4,5. The connections be- tween algebraic combinatorics and computa- Mansour: Were there specific problems that tional complexity extend further beyond these made you first interested in combinatorics? applications, and another goal is to understand Panova: No specific problem, but rather the 1R. P. Stanley, Log-concave and unimodal sequences in algebra, combinatorics, and geometry, In Graph theory and its applica- tions: East and West (Jinan, 1986), volume 576 of Ann. New York Acad. Sci., pages 500–535. New York Acad. Sci., New York, 1989. 2J. Huh, Milnor numbers of projective hypersurfaces and the chromatic polynomial of graphs, J. Amer. Math. Soc. 25:3 (2012), 907–927. 3M. Haiman, Hilberts schemes, polygraphs, and the Macdonald positivity conjecture, J. Amer. Math. Soc. 14:4 (2001), 941–1006. 4C. Ikenmeyer and G. Panova, Rectangular Kronecker coefficients and plethysms in geometric complexity theory, Adv. Math. 319, (2017), 40–66. 5P. B¨urgisser,C. Ikenmeyer, and G. Panova, No occurrence obstructions in geometric complexity theory, J. Amer. Math. Soc. 32 (2019), 163–193.

ECA 2:1 (2022) Interview #S3I3 2 Interview with Greta Panova problem style as a whole. I liked its problem- Mansour: What would guide you in your re- solving nature and the fact that I could start search? A general theoretical question or a working on a problem without much back- specific problem? ground knowledge. Panova: Usually both. I had to start with Mansour: What was the reason you chose some area I want to understand or find con- Harvard University for your Ph.D. and your nections to and then look for specific problems advisor Richard Stanley? there to help me explore further. Often other Panova: Initially my intentions were to do researchers would approach me with more con- algebraic number theory and went to Har- crete problems, which is usually a very enlight- vard as one of the best places for that. Af- ening opportunity to learn about a new sub- ter gaining more exposure across math fields, I area and find more connections. I am a prob- carefully reexamined my interests and what I lem solver, and ultimately it is the concrete liked about math and decided to do combina- problems that keep me awake at night. torics. I knew Richard Stanley from the fresh- Mansour: When you are working on a prob- man problem-solving seminar at MIT and it all lem, do you feel that something is true even seemed like a natural choice. before you have the proof? Mansour: What was the problem you worked Panova: Usually yes, but I could be dialectic. on in your thesis? I would try to prove and disprove at the same Panova: There were several little problems I time until it is clear which way it goes. solved during my Ph.D. and some went into Mansour: What three results do you consider my thesis6,7,8. They were all some form of the most influential in combinatorics during enumeration of permutations or tableaux using the last thirty years? tools from algebraic combinatorics like sym- Panova: Answering the question literally, in- metric functions, RSK, etc. The main prob- fluential would be the results which lead to lem was the enumeration of standard Young a lot of subsequent work, and as such per- tableaux of certain truncated shapes, the ones haps not specific Theorems, but rather con- obtained by removing a partition from the up- jectures or newly defined objects would top per right corner of a Young diagram (in English the list. Specifically, these would be (in no notation). Such objects had not been studied particular order): the discovery of cluster al- before. Ron Adin and Yuval Roichman had gebras by Fomin and Zelevinsky11; the study noticed experimentally that for certain shapes of dimer models starting with the work on the number of SYTs (linear extensions) seems the Aztec diamond initiated by Cohn–Elkies– to have product formulas since they did not Kuperberg–Larsen-Propp12 and greatly ex- have large prime factors9. They had asked panded by Kenyon–Okounkov–Sheffield13 and Richard Stanley about this phenomenon and evolved in the area of integrable probability he passed it on to me to solve. In order to solve driven by A. Borodin, I. Corwin, and many it, I used symmetric functions, complex anal- other famous mathematicians14. The study of ysis, volumes of polytopes, etc, and figuring diagonal harmonics with the flagship results – all these techniques out was quite enlightening the n! conjecture, proven by Haiman, and the to me and got me interested in their natural subsequent “Shuffle conjecture” of Haglund– continuation within integrable probability10. Haiman–Loehr–Remmel–Ulyanov15, more re- 6G. Panova, Bijective enumeration of permutations starting with a longest increasing subsequence, Discrete Math. Theor. Comp. Sci. Proc. (2010), 973–982 7A. Crites, G. Panova, and G. Warrington, Separable permutations and Greene’s theorem (2010), Ars Combin. 128 (2016), 103–116 8G. Panova, Tableaux and plane partitions of truncated shapes (2010), Adv. in Appl. Math. 49:3-5 (2012), 196–217. 9Subsequently they independently solved and published this: R. Adin, R. King, Y. Roichman, Enumeration of standard Young tableaux of certain truncated shapes, The Electronic J. Combin. 18(2) (2011), #P20. 10Integrable probability is the area at the intersection of statistical mechanics and probability which studies integrable particle models, see e.g. https://en.wikipedia.org/wiki/Integrable_system. 11S. Fomin and A. Zelevinsky, Cluster algebras I: Foundations, J. Amer. Math. Soc. 15 (2002), 497–529. 12N. Elkies, G. Kuperberg, M. Larsen, and J. Propp, Alternating-sign matrices and domino tilings, J. Algebraic Combin. 1:111–132 (1992) 219–234. 13R. Kenyon, A., Okounkov, and S. Sheffield, Dimers and amoebae, Ann. of Math. (2) 163 (2006), 1019–1056. 14See https://www.claymath.org/events/cmi-himr-integrable-probability-summer-school. 15J. Haglund, M. Haiman, N. Loehr, J. B. Remmel, and A. Ulyanov, A combinatorial formula for the character of the diagonal coinvariants, Duke Math. J. 126 (2005), 195–232.

ECA 2:1 (2022) Interview #S3I3 3 Interview with Greta Panova cently proven by Carlsson-Mellit16, and all tinguish the core. the work in symmetric functions these conjec- Mansour: What do you think about the dis- tures/results have motivated over the past 30 tinction between pure and applied mathemat- years. This is only within algebraic combi- ics that some people focus on? Is it mean- natorics, as of course, there have been major ingful at all in your case? How do you see the breakthrough results in other areas of combi- relationship between so-called “pure” and “ap- natorics. plied” mathematics? Mansour: What are the top three open ques- Panova: As long as theorems are being proven tions in your list? and mathematics is being developed, it could Panova: There is one major open problem be considered “pure”. I would consider “ap- – distinguishing the VP from VNP in arith- plied” that part of math that usually falls metic complexity theory17, which seems more into modeling and engineering and solves their accessible than P vs NP18. Specifically in alge- problems rather than proving new math theo- braic combinatorics: the “combinatorial inter- rems. Most of the mathematics we do and pub- pretation” of Kronecker coefficients and all the lish in journals like ECA qualifies as “pure” by other “mysteriously” nonnegative coefficients that measure, and further division is meaning- and structure constants. Such interpretations less. may probably not exist, following Igor Pak’s Mansour: What advice would you give to idea that Kronecker coefficients could be prov- young people thinking about pursuing a re- ably not in #P (under some reasonable com- search career in mathematics? putational hypothesis). Panova: Do mathematics for its beauty and Mansour: What kind of mathematics would the fun of the Eureka moment when you solve a you like to see in the next ten-to-twenty years problem. Do not be afraid of the long academic as the continuation of your work? path because at every step there are multiple Panova: I would like to see further devel- opportunities – math is used in so many areas opment in the connections between algebraic in the industry besides academia, it is worth combinatorics and computer science and prob- the journey. ability. I hope to see progress towards the ques- Mansour: Would you tell us about your in- tions listed above. terests besides mathematics? Mansour: Do you think that there are core or Panova: I have an interest in molecular bi- mainstream areas in mathematics? Are some ology and do some collaborations helping to topics more important than others? model molecular dynamics in the DNA repair Panova: Yes. Most of the perceptions of processes. While this is still “research work”, “core” and “important” stem from the opin- it is unrelated to my main mathematical re- ions of the experts and are often function on search career. the number of researchers working in a given On a more personal level, I really like ex- area. Yet there are many subareas with a lot ploring nature. I go hiking, mountaineering, of activity due largely to the variety and ac- and I like to capture the beauty of nature with cessibility of the questions. I would measure photographs. I used to paint and draw, but I the importance of an area by its connectivity have not pursued this much recently. to other areas of mathematics or other sciences Mansour: In a series of four papers, co- and define its influences via the power and ap- authored with Morales and Pak19,20,21,22, on plicability of its methods. Then we would dis- Hook formulas for skew shapes, you obtained 16E. Carlsson and A. Mellit, A proof of the shuffle conjecture, J. Amer. Math. Soc. 31 (2018), 661–697. 17For example, see A. Shpilka and A. Yehudayoff, Arithmetic Circuits: A Survey of Recent Results and Open Questions, Foun- dations and Trends in Theoretical Computer Science 5:3–4 (2010), 207–388. ? 18For example, see S. Aaronson, P = NP , in Open problems in mathematics, Springer, Cham, 2016, 1–122 19A. H. Morales, I. Pak, and G. Panova, Hook formulas for skew shapes I. q-analogues and bijections, J. Combin. Theory, Ser. A 154 (2018), 350–405. 20A. H. Morales, I. Pak, and G. Panova, Hook formulas for skew shapes II. Combinatorial proofs and enumerative applications, SIAM J. Discrete Math. 31 (2017), 1953–1989. 21A. H. Morales, I. Pak, and G. Panova, Hook formulas for skew shapes III. Multivariate and product formulas, Algebraic Combinatorics 2:5 (2019), 815–861. 22A. H. Morales, I. Pak, and G. Panova, Asymptotics for the number of standard Young tableaux of skew shape, European J. Combin. 70 (2018), 26–49.

ECA 2:1 (2022) Interview #S3I3 4 Interview with Greta Panova interesting and important results regarding the from Representation theory, are used to de- Naruse hook-length formula23 which has al- scribe the decomposition of the tensor product ready motivated a great deal of recent interest of two irreducible representations of a symmet- in the enumeration of skew tableaux and re- ric group into irreducible representations. How lated topics. Would you tell us about this for- do they come into play in combinatorics in gen- mula, the main motivation behind this project, eral and in your research in particular? and some potential applications of techniques Panova: Ever since their introduction by developed in these papers? Will this series con- Murnaghan25 more than 80 years ago, they tinue with new surprising results and applica- have posed a major problem – to give any kind tions? of positive combinatorial formula for them. Panova: One of the most fascinating classical Kronecker coefficients can be expressed using results in algebraic combinatorics is the Hook- characters of Sn, Schur functions, and even length formula of Frame–Robinson–Thrall24 contingency arrays. Yet, their inherent non- for the number f λ of Standard Young Tableaux negativity (as multiplicities of irreducible rep- of a given shape λ, equivalently the dimen- resentations) and their semigroup property are sion of the irreducible Sn representation of completely mysterious from all these (nonpos- the Specht module of λ, which gives f λ as n! itive) combinatorial formulas. Ever since we divided by the product of hooks of λ. For started looking at them with Igor Pak, I have SYTs of skew shapes no such formula exists, been trying to understand them and answer as can be seen from the special case of f δn/δn−2 this question, perhaps in the negative formally given by the Euler numbers. In 2014 Hi- using computational complexity notions. The roshi Naruse presented a remarkable formula various formulas have given us a lot of partial expressing f λ/µ as n! times a sum over “ex- results, and also implications to other prob- cited” diagrams of µ inside λ weighted by lems (like Sylvester’s26 unimodality for the the inverse product of hook lengths of each number of integer partitions inside a rectangle, diagram. Naturally, such a beautiful result ref. our papers with Igor Pak). A major moti- needed a “combinatorial” explanation and we vation to study them came from GCT, where set on to [re]prove it by first generalizing it to they can be used to understand the represen- q-weighted enumeration over skew SSYTs and tation theory of the coordinate rings for the reverse plane partitions and proving those re- determinant and permanent and thus hope- sults algebraically, bijectively, and later on via fully distinguish them and possibly prove that recursions and non-intersecting lattice paths. VP 6= VNP . In the course of our investiga- Thanks to the positive-sum and nice weights tions, we disproved a cornerstone conjecture the formula proved to be useful for applica- in GCT5, but we also understood more about tions, mostly related to asymptotic results (for them. the number of skew SYTs to lozenge tilings and Mansour: In the paper entitled Asymptotics more refined asymptotics and probabilistic be- of symmetric polynomials with applications to havior of SYTs). I am expecting to see more statistical mechanics and representation the- such asymptotic applications of this formula ory, co-authored by Gorin27, you developed and I am hoping for further connections to a new method for studying the asymptotics Schur functions. The new, though not entirely of symmetric polynomials of representation- surprising, results concern its deformations, for theoretic origin as the number of variables example to Grothendieck polynomials and the tends to infinity. Would you explain this associated standard increasing tableaux. method and some of its applications briefly? Mansour: Kronecker coefficients, as ’tools’ Models from statistical physics have always 23H. Naruse, Schubert calculus and hook formula, talk slides at 73rd S´em.Lothar. Combin., Strobl, Austria, 2014; available at tinyurl.com/z6paqzu. 24J. S. Frame, G. de B. Robinson, and R. M. Thrall, The hook graphs of the symmetric group, Canad. J. Math. 6 (1954), 316–324. 25D. Murnaghan, The analysis of the direct product of irreducible representations of the symmetric groups, Amer. J. Math. 60:9 (1938), 44–65. 26J. J. Sylvester, Proof of the hitherto undemonstrated fundamental theorem of invariants, Philos. Mag. 5 (1878), 178–188, reprinted in: Coll. Math. Papers, vol. 3, Chelsea, New York, 1973, 117–126. 27V. Gorin and G. Panova, Asymptotics of symmetric polynomials with applications to statistical mechanics and representation theory, Ann. Probab. 43:6 (2015), 3052–3132.

ECA 2:1 (2022) Interview #S3I3 5 Interview with Greta Panova been a rich source of interesting problems for netics and reaction kinetics. Subsequently, the combinatorics and probability. Are there spe- fields of systems biology and computational cific problems in this direction in your research biology (genetics and neuroscience) emerged, plan for the near future? but their level of abstraction and generality is Panova: Indeed, as I have mentioned above, nowhere close to what we have seen in theoreti- integrable probability uses symmetric func- cal physics. The main issue comes from the in- tion theory. The normalized Schur functions herent complexity of living systems and life’s can be interpreted as a variant of the mo- uniqueness. Despite the great variety of liv- ment generating functions for observables in ing organisms, the underlying biology is all too the lozenge tiling model (e.g. positions of hor- similar in its building blocks and basic mech- izontal lozenges near the boundary). Their anism and at the same, these are too complex asymptotic behavior gives us the probability to pick apart. distributions of certain lozenges and can be Mansour: You have extensive experience with further used to derive limit surfaces and be- major mathematics competitions such as In- havior of such dimer models. These meth- ternational Mathematics Olympiads and Put- ods, however, rely strongly on the geometry nam. Do you think that mathematics com- of the domain/boundary conditions and dimer petitions play a crucial role to inspire young weights, and extending our understanding fur- students for a research career? ther is still ongoing. Some specific problems Panova: Mathematical competitions defi- concern the asymptotics of normalized skew nitely help popularize mathematics among stu- Schur functions or the study of tiling models dents and also help them develop problem- with long-range interaction which we encoun- solving skills, which are useful also outside aca- tered when studying the seemingly unrelated demic math like tech and finance jobs. The problem on maximal Schubert polynomials. caveat is that this very inspiring (and fun!) Mansour: Combinatorics is full of important experience could also be slightly misleading formulas. Which three are your favorite? since, unlike competitions, research problems Panova: The original hook-length formula are rarely solvable in 3 hours. for the number of SYTs23 has been a major Mansour: In your work, you have extensively source of inspiration and beautiful results. The used combinatorial reasoning to address im- Lindstr¨om28, Gessel–Viennot29, and Karlin– portant problems. How do enumerative tech- MacGregor30 determinantal formula for count- niques engage in your research? ing non-intersecting lattice paths has been use- Panova: Enumerative techniques help from ful across the areas from algebra to probabil- the beginning by breaking the problem into ity. The matrix-tree theorem and Weyl deter- possibly smaller structures, making simpler minantal formula are also up on the list. models, finding symmetries and recursions. Mansour: You were one of the panelists at Generating functions are also a very powerful the workshop, “Towards a new theoretical bi- tool by itself. ology,” in 2018 at the University of Pennsylva- Mansour: It is a fact that not many women nia. Would you tell us about the main differ- follow a professional career in mathematics. It ences between the new and the old? How does is a discussion around the globe on how to get combinatorics involve there? more women into mathematics. What do you Panova: I believe I was on this panel be- think about this issue? What should be done cause I am a mathematician with some work in the next ten years to involve more women in molecular biology, but it is unrelated to my in mathematics? work in combinatorics. The discussion in this Panova: Algebraic combinatorics is doing workshop was focused on why biology has not something right, as it seems that the propor- been able to take such advantage of mathe- tions of women in this field are higher than matical methods and developed as theoretical in most other areas of math. A lot of the physics has. The “old” theoretical biology re- current efforts focus on recruitment at later volved mostly around models in population ge- stages, but I think the issues start already in 28B. Lindstr¨om, On the vector representation of induced matroids, Bull. London Moth. Sot. 5 (1973), 85–90. 29I. Gessel and G. Viennot, Binomial determinants, paths, and Hook length formulae, Adv. Math.58 (1985), 300–321. 30S. Karlin and J. G. McGregor, Coincidence probabilities, Pacific J. Math. 9 (1959), 1141–1164.

ECA 2:1 (2022) Interview #S3I3 6 Interview with Greta Panova middle school. There are too many stereotypes thought process for the proof of one of your poisoning the experience from early on – from favorite results? How did you become inter- gender biases to the unpopularity of math as a ested in that problem? How long did it take subject (especially in the US). We should each you to figure out the proof? Did you have a do our part in debunking these stereotypes at “eureka moment”? every level. Panova: I must say that the older and more Mansour: You are the recipient of the IMI experienced I get, the less surprise and excite- Prize for the year 2020, a prize awarded by ment of the “eureka moment” I have. Recently the Institute of Mathematics and Informatics my solutions have been gradually built up from of the Bulgarian Academy of Sciences. The smaller problems and often result from finding prize will be presented during the International connections. My favorite results are “Rectan- Conference “Mathematics Days of in Sofia” in gular Kronecker coefficients and plethysms in 2021. How do you feel about going back to the geometric complexity theory”4 (with C. Iken- city you were born to obtain a prize in math- meyer), “Asymptotics of symmetric polynomi- ematics? Do you think that you will be whis- als with applications to statistical mechanics pering, ”yes, I did it, grandma!” while your and representation theory”26 (with V. Gorin), eyes will have been filling with tears? and “Hook-length formulas for skew shapes Panova: Too bad my grandmas died more I”18 (with A. Morales and I. Pak). These were than 20 years ago... It is a great honor to all multilayered projects and no problem there be recognized in my own land31 and it is es- was solved at once. For the sake of example, pecially important to me as an opportunity to without being too concrete, I can describe a introduce my field of algebraic combinatorics typical process: first I would try to understand which is not represented in Bulgaria. the objects in the problem usually by interpret- Mansour: You have some of your paintings on ing them geometrically or algebraically (e.g. your web page. Have you ever planned to be a using symmetric functions), and I try to visu- painter? How would you compare the two cre- alize the problem as much as possible. Unlike ative activities: painting and doing mathemat- many combinatorialists, I rarely start with do- ics? Stendhal syndrome, a strange aesthetic ing small examples, I would rather encode the sickness, is described as a psychosomatic con- structure in full generality, look for invariants, dition involving rapid heartbeat and fainting special characteristics, etc. Exploring different occurring when an individual becomes exposed models ultimately could lead to a more “famil- to artworks of great beauty. Do you think that iar” situation that can be handled with exist- we, mathematicians, experience a similar syn- ing tools. drome when we see an outstanding result or an Mansour: Is there a specific problem you excellent paper? If yes, would you like to offer have been working on for many years? What a name to this syndrome? progress have you made? Panova: Up until college I was planning to Panova: Kronecker coefficients have always be an architect which seemed a good combina- been burning a hole in my mind. We have tion of math and painting. Aesthetics in art certainly understood them better throughout and math could be indeed quite similar to ex- the past 10 years, and that research has led periences. But unlike art, which can be widely to many other interesting connections and de- appreciated, recognizing mathematical beauty velopments. At the same time, the problem on requires more expertise. Personally, my enjoy- whether they are in #P or not is still out there ment of both math and art is in practicing with no solution in sight, so it would be hard them – the joy and satisfaction for finding a to tell how close we are. nice solution are quite similar to those I had Mansour: Professor Greta Panova, I would experienced by expressing on paper the image like to thank you for this very interesting in- in my head. terview on behalf of the journal Enumerative Mansour: Would you tell us about your Combinatorics and Applications.

31but I can’t be a prophet there per the old saying.

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