Barry Simon's 60th Birthday Celebration:
Reminiscences of Friends, Relatives,
and Colleagues

This website collects short stories from Barry Simon's many colleagues spanning his long, distinguished, and productive career as a leading researcher in mathematical physics. Some of these stories will be reproduced in the Festschrift volume in his honor to be published in the Proceedings of Symposia in Pure Mathematics, edited by Percy Deift, Fritz Gesztesy, Peter Perry, and Wilhelm Schlag. For further information on the Festschrift Volume and 60th Birthday Conference to be held in Barry's honor, please see the conference website.

If you would like to contribute a story or reminiscence (or photo), please e-mail your contribution to
Cherie Galvez. For further information, please contact Fritz Gesztesy or Peter Perry.



Mark Ashbaugh   |   Yosi Avron  |  Gary Chase   Michael Cwikel & Grigori Rozenblum   |  E. Brian Davies
Bill Faris  |  Charles Fefferman   |   Alex Figotin   |   Jürg Fröhlich   |   Fritz Gesztesy   |   Vincenzo Grecchi  
George Hagedorn   |   Evans Harrell   |   Ira Herbst   |   Robert Israel   |   Sergey Khrushchev  Abel Klein
 Woody Leonhard   |   Doron Lubinsky   |   Krishna Maddaly   |   Edward Nelson    Vipul Periwal
 Peter Perry   |   Mason Porter   |   Grigori Rozenblum   |   Beth Ruskai   |   Lorenzo Sadun   
 Barry Simon  |   Rick Simon   |   Yakov Sinai



Mark Ashbaugh


The lawnmower

I was a graduate student with Barry at Princeton in the late 70s. Usually my meetings with him were relatively brief and concentrated on the problems I was working on at the time. But one day I went to his office and there was a lawnmower occupying a large space behind his desk. I guess I looked at it sort of funny, but for whatever reason Barry felt the need to explain what he was doing with a lawnmower in his office on the third floor of Jadwin Hall. The story went something like this:

Barry needed to take his lawnmower in for repair, so he set off with it when he came to the office planning to drop it off at the repair shop later in the day. But then he learned that his services were needed to pick up the Math. Physics Seminar speakers of the day, the Chudnovsky brothers. Of course this necessitated removing the lawnmower from the car, and the logical place for it was his office!

That explained, we went on with the mathematics. Maybe the lawnmower remained for another day or two. And the talk by the Chudnovsky brothers is another story. Perhaps only one of them was the invited speaker, but it wouldn't have mattered . . . .




Yosi Avron

In the early eighties, Murph Goldberger was the president of Caltech. Murph was a great fan of Barry since their Princeton days and concocted a scheme to try and lure Barry from Princeton to Caltech. The scheme started innocently enough by inviting Barry to spend a year in sunny California as a Fairchild Scholar. Murph's plan indeed worked like charm and a year of leave turned out to be a permanent move.

Princeton, at the time, was the Mecca of mathematical physics. It probably had the largest math physics group. Caltech, at the time, and as far as mathematical physics was concerned, was like the rest of Saudi Arabia: a desert (with a lot of oil). As you probably know, Barry thrives in company. So he looked for someone to accompany him to the desert. After a lot of fruitless searching, Barry must have remembered that I had some practical experience living in a real desert and asked me to join him. The arrangement was curious. I must have been the only Princeton Assistant Professor who had his paycheck sent to California. And, I remember that the bank teller once asked me if I could swing such a trick for her. She preferred the Bahamas, however. Anyway, since I had no official standing at Caltech, I decided to decorate myself as the Fairbaby Scholar.

The Fairkid year we spent together was a remarkable year, for I had Barry almost all to myself. In Princeton, where I first met Barry as his postdoc, I would get as an appointment the walks to the parking lot, and occasionally a ride to Edison spending a pleasant Shabat with Barry and Martha. How much leisure we had in this Fairkid year is evidenced by the fact that, hold on to your chairs, Barry and I used to go swimming regularly at lunch time at the Caltech swimming pool!

Can you imagine how many papers did not get written because of my bad influence on Barry! Swimming at the Caltech pool was very good for me: Here was a place where I could beat Barry fair and square.

Barry, on the other hand, felt very guilty about this waste of time. To comfort himself he told me that the lost hours at the pool would be paid up by gained years in better health. Well, what could be more appropriate than to celebrate this wisdom twenty years later, at his 60th anniversary party.

Let me now tell you a story involving Ira Herbst and Barry. I was an overwhelmed Wigner fellow at Princeton, working with Ira and Barry and we were quite close. Ira came back startled from one job interview, I forgot where. The chairman had asked him if he ever wrote a wrong paper. Ira was shocked and said "Of course not!" The reaction of the chairman was unexpected. He said: "Then you do not write enough." Now, nobody could ever accuse Barry of not writing enough. But I take the credit for writing a wrong paper with Barry. Here is how this came to be: There was a lot of excitement in Caltech when Voyager first sent those spectacular pictures of the rings of Saturn. I had learnt that Saturn appears to have infinitely many rings from a math grad student at Caltech. Barry and I were working at the time on almost-periodic Schrödinger equations and were fascinated with fractal spectra. I knew about Hill lunar theory and Barry had just written a review of Arnold's book on Mechanics. This led us to make a theory where the near incommensuration of the periods of the moon of Saturn (and also involved the Sun) gave rise to rings with fractal structure. Peter Goldreich, the czar of planetary physics in Caltech, did not like the theory because it was linear stability. But Feynman did because it was simple. The theory could not account for the order of magnitude for the observed gaps and so turned out to be wrong.

Barry's time axis is divided into AC and BC: Before Caltech and After Caltech. In the BC era Barry had difficulties deciding if his heart lay with constructive field theory, statistical mechanics or quantum mechanics. In the AC period the die was cast in favor of quantum mechanics and spectral theory. Barry also contracted a chronic strain of PC flu.

Since I am an old-timer let me reminisce about the prehistoric BC era.

At Princeton there were the lunch time seminars and the Math-Phys seminars. In the lunch time seminar, Barry was the prima ballerina. (Can you imagine Barry on his tiptoes?) He would normally either tell a new result of his or a new result of someone else. With Dyson, Lieb and Wightman in the audience, most grad students and postdocs, were too terrified to expose their slowness if they were to ask an innocent question. Most of the time, nobody dared open his mouth. The notable exception was the fresh grad student from Harvard, Alan Sokal, who never had a fear of authority and was sufficiently smart and self-confident to argue with Barry.

The math phys seminars were a different business. There was an outside speaker most of the time. Wigner would usually show up and ask his typical Wignerian questions. Barry would sit in the audience and write a paper. From time to time he would look up from his notes and ask a question that would unsettle most speakers: Someone in the audience seemed to know more about what he was talking about than himself. Sometimes, at the end of the talk, Barry would go to the board and give his version of the proof, which was always slick.

Barry, you are now 60. Most of us probably do not enjoy being reminded about our advanced age, but I think that one of the nice things about you, Barry, is your optimism. You probably, enjoy being 60! I wish you fun with math and good health in the next sixty years.




Gary Chase


Congratulations to Barry on his 60th birthday -- as a college classmate I am over-whelmed but not surprised by his many accomplishments. Here is a little story you might like:

As undergraduates at Harvard, several of us took the Real Variables course given by Professor Lynn H. Loomis. Loomis came to class with few or no notes and lectured fluently. One day he was writing a proof on the blackboard and paused briefly, scratching his head. He stepped back from the board and looked into the audience where he saw Barry. Loomis said "Are you thinking what I'm thinking?" and Barry said "Yes." Loomis said "I thought so" and then went back and completed the proof. The rest of us had no idea what this thought was, since it was not verbalized by either of them! This incident was one of many that convinced us that Barry was uniquely gifted in such matters. 

It was a privilege to attend college with this extraordinarily brilliant man who also has a great sense of humor and has proved a wise and guiding mentor over the years.




Michael Cwikel

Grigori Rozenblum


Dear Barry:

We would like to express our warmest greetings and best wishes to you and your family on the (ongoing!) occasion of this lovely celebration. It also provides a welcome occasion for us to thank you heartily for your big part in promoting the estimate which bears both our names, together with Elliott Lieb's.

Your observation in 1975 that using some variant of ideas from interpolation of operators together with simple properties of the Hilbert-Schmidt class might be relevant, was of course crucial for my (M) proof of that estimate. After I (M) showed that your wonderful observation was indeed correct, you remarked something like: "This is something that an engineer could do." Let us understand that as an expression of admiration for talented engineers.

I (M) can still clearly recall your typically energetic and totally Barryesque exhortations in 1975 in the Fine Hall coffee room to all those present to solve the problem which would give these estimates.

Soon after Elliott and Michael found proofs (Elliott's using methods very different from those that you had suggested), you learned that my work (G) in 1972 contained another proof of this estimate. When you met me (G) in Leningrad in 1977 you said something like: "Oh, it is your theorem that I stole."

Please, as we know you will, keep on exhorting and good naturedly teasing and provoking everyone, including yourself, to engage wholeheartedly in this wonderful business. And we look forward to many more exciting consequences of your exhortations!

With all good wishes!

Ud Mea v'Esrim!





E. Brian Davies


In 1983 Derek Robinson invited me to visit him at the Mathematical Institute in Canberra for a month. As one of the inducements he mentioned that he had also invited Barry Simon for the same period. The prospect of seeing Barry, Derek and kangaroos was enough to make my decision, and in July 1983 I set off on the gruelling journey.

I was very surprised shortly before my departure to hear from Derek that he was unable to avoid a commitment to go to a conference in Japan, and would not return until ten days after my arrival. Barry arrived about the same time as myself, and I asked him a problem about heat kernels of Schrodinger operators which I had solved in one dimension by a method that could not be extended to higher dimensions. At that time I had read several of the papers on hypercontractivity, a concept that was invented specifically to solve problems in quantum field theory, in which there are an infinite number of degrees of freedom.

Barry listened to my question carefully and agreed that some progress should be possible. The very next time I saw him he told me that he had solved the problem by an improvement of the standard hypercontractive estimates that made use of the finite dimensionality. He then proceeded, without notes, to give me a lecture on the subject, explaining every step in detail, including the infinite summation procedure that allowed one to pass from L2
® Lp bounds to L2 ®  L¥ bounds by controlling the constants involved.

Although very impressed, I had the temerity to suggest at the end of his lecture that although he had clearly done what was needed, I did not like his solution aesthetically, and would prefer an account that depended on differential inequalities. I had the feeling that this would yield better constants and be in some sense more natural. On the next occasion Barry rewrote the entire account in this language, and we realized that this was going to have enough ramifications to occupy the entire month. By the time Derek got back we were fully committed to the project, and I now feel embarrassed that I did not spend nearly enough time talking to him. Derek was, however, the person who coined the term ultra-contractivity, which was the focus of almost all of my research over the next ten years.

A research relationship is, of course, not symmetrical, and for Barry it was just one of many different projects he pursued in that decade. Indeed I wonder whether his main memory of the month was quite different. He had gone to Canberra with Martha and his four children; together they might have comprised the entire Orthodox Jewish community there. With typical thoroughness he arranged for kosher meat to be delivered to him from Sydney every few weeks. The Jewish butcher had agreed to prepare a parcel and then put it in a deep freeze before sending it by rail. On one occasion it did not arrive, and I was involved in a very strange mathematical discussion, which was punctuated every hour or so by long conversations between Barry and the delivery service, in which he explained that if his parcel did not arrive within a few hours he would have to throw it away. I believe that eventually everything was okay. Surviving in Canberra for a month with his family while observing Orthodox rules was just another challenge of the type that Barry always seemed to relish. Perhaps the absence of such problems in London, which has a very large kosher Jewish community, was one of the reasons why he has visited me on a number of occasions there.




Bill Faris


Barry and friends in the French Alps, near Geneva. It was a hike to Pt. de Miribel on April 8, 1973.

That's Barry under attack on the left. To his right are Madeleine Lapointe, Becky Thomas, Charles Stuart, Christine Stuart, Larry Thomas.

The next day Stephan Faris was born in Geneva. Not long after, Barry and I paid a visit to the room where Madeleine was resting and holding Stephan. Afterward we noticed that the tissue box by the side of the bed had become completely covered with equations.




Charles Fefferman

I have a cute Barry quote from a visit to Princeton in the late 80's or early 90's:

"To first approximation, the human brain is a harmonic oscillator."

He made this remark in private conversation as we walked around the Princeton campus.




Alex Figotin


Taken in Banff, September 2005



Jürg Fröhlich


I first met Barry(-boy) in front of the conference building of the Les Houches summer school, back in 1970. He introduced himself like this: "Hi, I'm Barry Simon from Princeton University." I must have replied roughly as follows: "Good afternoon,  Professor Simon. I guess I am Juerg Froehlich, a student from ETH in Zurich. How are you?"

This was to be the beginning of a wonderful friendship that has lasted to this day.

In the summer of 1970, I had just started my graduate studies as a student of Klaus Hepp, who was one of the lecturers at that school. (Of course, Klaus arrived at Les Houches late and left early, as he does at every conference. After his departure, Konrad Osterwalder and I were confronted with the task of proofreading and editing his lecture notes – quite a formidable task). Barry, however, who is only a few months older than I am, was already on his way towards becoming a faculty member at Princeton. He would always beat me in everything! He got married before I did; he has more children than I do; he started to play with computers before I did (if I ever will); he quit physics and became a mathematician before I did (if I ever will), etc...

Barry was a very lively "student" at that famous Les Houches school (constructive quantum field theory and statistical mechanics). He was already pretty voluminous, physically, but also mentally, as he appeared to always know more than the lecturer. He was engaged in a friendly competition with Alain Connes, also a student at that school: The competition was about who of the two was faster in simplifying the proof of the lecturer or rendering it more elegant. I will only say that both of them performed admirably!

Barry was almost always writing some manuscripts, even during lectures. Nevertheless he appeared to always understand what was being taught to us. In the library, a new Simon preprint could be found every week – the school lasted for eight weeks. These preprints were handwritten. Some of them were co-productions with people like Graffi, Grecchi (Borel summability of the anharmonic oscillator), or the  late Raphael Hoegh-Krohn (hypercontractivity). These preprints were consumed like French croissants by the other kids (like myself), because they were very clearly written and not enormously technical and could therefore be understood by people whose level was not terribly advanced yet.

David Ruelle presented some rather qualitative lectures about statistical mechanics. (He likes to be qualitative and write only few formulae, in his lectures.) Barry asked him: "David, when are you going to start to do some serious work?" David replied: "Go to the library and read my paper about superstable potentials. This is as serious as I can get." I imagine that the contents of that paper will appear in Barry's second book on statistical mechanics that we are all awaiting impatiently.

Barry must always have been a good eater. I remember that excursion to the Aosta valley. At the "maison de Filippo," Barry ate unbelievable amounts of good food. He would occasionally disappear on the balcony of the restaurant to take a breather and get ready for the next dish. I drove Barry back to Les Houches; the car was tilting  towards its right side where Barry was sitting, and I had probably more than that half a part in a thousand of alcohol in my blood stream. But we safely reached the school.

My next encounter with Barry was in 1972 when he taught a graduate course in the "3ieme cycle" of French-speaking Switzerland; of course, he taught in English. That course was the basis for "The P(\phi)_2 Euclidian (Quantum) Field Theory," one of his many books, and quite a successful one that is still occasionally consulted by aficionados of mathematical quantum field theory (perhaps because it contains those famous "Fröhlich bounds"). In 1973, he showed up in Geneva, where I was a postdoc, with the famous Lieb-Simon results on Thomas-Fermi theory in his bag. He complained about the difficulties one faces when one wants to enter the "Republique de Geneve" (tuberculosis and ... tests, residence permit, etc.) I gave him a ride to his headquarters, in my beautiful yellow FIAT. We got caught in a minor accident: A lady drove into the right side of my car, where Barry was seated. (She was probably a prostitute, as it turned out later, and she never paid for the damage, although it had been her fault.) Luckily, neither Barry nor I was hurt, and the car was soon repaired.

I later learnt from Elliott Lieb that when he and Barry were working on Thomas-Fermi, during a stay at IHES near Paris, Barry not only discovered lots of lemmas, but he also discovered that Swiss pralines are kosher.

In 1974, Barry(-daddy) and Arthur Wightman engineered an offer for me to join them at Princeton as the successor of Michael Reed at the math department. This was to become the only period in my life when I was officially considered to be a mathematician. Our stay at Princeton became a turning point in my career – not only thanks to Barry, but also thanks to Elliott Lieb, Arthur Wightman, Ed Nelson and, especially, Erhard Seiler and Tom Spencer with whom I co-authored what are, perhaps, my best scientific papers (not surprisingly).

I had to learn many things – I still do. For example, I had to learn that when I would say "hello" to Barry in a corridor of Jadwin Hall, in the morning, and he would not even turn his head towards me, it did not mean that he was angry at me; it just meant that he didn't have even five seconds to lose. (Well, I guess those Brooklyn kids do not have those terribly refined manners.) But Barry had wonderful qualities of all kinds! For example, he always applied for money from the NSF, not just for himself but also for Valja Bargmann and for me, and probably for further members of the club. And he apparently got the money. He was unbelievably well organized and efficient! He would always write the paper when the research was done, and he did it in five percent of the time ordinary mortals need to write such papers. I once told Barry that I always wanted to be at a department with a colleague like him, who takes care of essentially everything and doesn't forget anything. He said: "Juerg, I only know one place where you could have a colleague like me." (He had already moved to sunny California.)

At Princeton, he still wrote his manuscripts during seminars, just to ask the right questions at the end or point out errors. The brown-bag luncheons were by and large "Barry Simon shows" where one could learn about his latest lemmas and theorems – I probably could have learnt functional analysis there if I had stayed at Princeton for a few more years; incidentally not just from Barry, but also from Ed. "Missed opportunities."

Then there were those annual Simon parties at Martha and Barry's house in New Brunswick, with Barry always occupying the most comfortable chair in the house, and with all the snacks within his reach.... You know, this could easily evolve into a one-hundred page novel. I've got to cut it short.

I believe I have seen Barry almost once a year, ever since. He visited me in France and then in Zurich. I guess he prefers Zurich over Paris, which was a good reason for me to move back to Zurich. Barry likes all the mountains near Zurich whose tops can be reached in a cable car. (But I believe he also comes to visit us for other reasons.)

Well, I guess Barry is still Barry-boy, playful and with lots of small pleasures to enjoy, in- and outside mathematics.

I am very grateful that Barry's and my paths crossed! I hope they will continue to do so for many more years, and I gladly volunteer to remain Barry's "mentee" (see his webpage) for the rest of my professional life, trying unsuccessfully to catch up with him. (I hope he will not lose his patience with me.)




Fritz Gesztesy


Close interactions with Barry have their great rewards — and perils!

While Barry's lightning mental agility, his extraordinary talent to strip the unnecessary clutter surrounding an argument, getting straight to its core, and his remarkable ability to see connections to related topics other than the obvious ones in question, are legendary, the following observations will sound familiar to many of us:

Scenario #1: You joyously walk into Barry's office to present him with a new idea, just to exit a few minutes later, your idea having been shred to pieces. "Back to the drawing board'' is sometimes his comment, with a broad grin on his face. All this sounds more cruel than it is: After all, you have just been saved from going down a cul-de-sac and you can start regrouping!

Scenario #2: You proudly walk into Barry's office to show him something new. Barry thinks for a second, then jumps up to the blackboard and explains to you in no uncertain terms what you "really had in mind.'' That's great, because at this point you realize a joint paper will eventually be written.

Scenario #3: You march into Barry's office and this time you're convinced you have a blockbuster at your fingertips. You start to explain to Barry, and then he says "time out'' and silence fills the room. After a bit of eerie silence you realize this time you're going to write a very nice joint paper with Barry. Of course, after a few more moments scenario #2 will be repeated, but that's quite alright!

Scenario #4: Barry asks you into his office and explains what he was struggling with lately. (He likes to put it this way, though: "I was banging my head against the wall about this...'') After he suggests jointly working on this you return to your office with a big puzzle in your hands. Those rare instances in which you can actually do the job asked of you and complete the argument are priceless.

•  Barry likes to pick on me since I'm usually not afraid of computing anything, well, almost anything (while he doesn't have the patience to do so!). So once in July of 1997, he confessed to me that he had a terrible contradiction in his long manuscript on "The classical moment problem as a self-adjoint finite difference operator'' (it later appeared in Adv. Math. 137, 82–203 (1998)), but he just couldn't find the error. So I was supposed to look at this. It was an intricate puzzle! I spent a day on it and well after midnight was sure I had found the error. So I e-mailed him what I thought was the culprit and slumped home to the apartment. Next morning I opened my e-mail and there was Barry pointing out that I was dead wrong. It was "back to the drawing board'' as he still grinned during our brown bag lunch meeting that day. I was dejected! Well, I had another day before going away with my wife to Hawaii, and I was not about to let this ruin our vacation! So I frantically computed like a dog and finally saw the light: This was it! I decided to treat myself to dinner and left after e-mailing him my second attempt to find the culprit. After returning from dinner late that night, I had received quite a different message from Barry. It started out: THANK YOU, THANK YOU, ... and went on like this for half a page.



Vincenzo Grecchi



Buffon once said, "The style is the man." I tell only one story showing the style and humour of Barry. Once in the last millennium, in Marseille, I was driving a car, accompanied by Barry and others; we were off to see Jean Bellissard. It was a lazy summer afternoon, and the car was turning slowly around the Bellissard palace in search of a free parking space. For a while, the silence was broken only by the continuous, strident call of the cicadas. I was not aware of having made a complete tour around the building (and of the vanishing hope of finding a parking spot) when I heard a clear unequivocal sentence: "two pi!"



George Hagedorn


Below is an amusing little story that shows Barry's good sense of humor and how quickly he could think of a clever comment.

Barry had many graduate students at Princeton. Although he treated us well, he used to kid around about abusing us or treating us as some sort of subhumans. It was all in good fun, and I always found it amusing.

In November 1976, the night that Jimmy Carter was elected president, Barry invited some of us to to have dinner and watch the election results on the television at the Simons' house in Edison, New Jersey. Shortly after I arrived, I was hanging my coat up in the closet when Barry's daughter Rivka pointed at me and said, "Daddy, what's that man's name?" Without the slightest hesitation, Barry replied, "Rivka, that's not a man, that's a graduate student!"





Evans Harrell


•  One of the rare categories in which I can compete pretty well with Barry is in the execrableness of our handwriting. I was at MIT as a postdoc when we wrote our long paper on the Stark effect. Back in those days, one actually wrote articles by hand and a secretary, using a device called a "typewriter" turned them into manuscripts, leaving blanks for formulae to be inserted. As a lowly postdoc I didn't get first pick of the secretarial staff, and the manuscript ended up in the hands of a well-intentioned but struggling secretary who would produce about one page per day, which was usually sent back multiple times with corrections, often amusing. One day a favorite adjective of Barry's, "operator-theoretic," came back as "operator neurotic," and I knew the manuscript was taking its toll on her. With lots of encouragement and little gifts she finished the manuscript after months of work, as the term ended. But she didn't return the next term — it was doubtless the last mathematical manuscript she ever typed.

•  Barry may or may not have said "This is my cross to bear" according to Ed Nelson, but might he ever have been a cross bear? The first time Barry's bearlikeness crossed my mind was at a party at his home in New Jersey, where even graduate students were invited, and little Rivka appeared looking for one of her toys. I think it may have been a stuffed animal, a "big horse" or something like that. Finding the toy was way beyond the powers of a graduate student, but Barry walked by in the next room so I sent Rivka in that direction, telling her "Just follow the big bear, and he'll find your toy." Bears have acute hearing, and I remember him growling, "I heard that!", but Rivka didn't hesitate at my description of her father.

Many years later Barry gave a seminar at Georgia Tech. In the audience was a colleague from another university, whose rather nice early work had been discovered and promoted by Barry, but who had been inactive for some time while struggling with mental illness. At the end of the seminar the visitor asked some rather peculiar questions, which went on and on. Barry handled them with his usual aplomb, but clearly something was amiss, so after everyone left I took my friend off to find his medication. When he was again rational, he told me that half way through the seminar, Barry had turned into an enormous grizzly bear before his eyes, and that he needed to distract the bear with mathematical questions, or the audience would be devoured!

  Barry has always been remarkable for his vast knowledge of mathematics, so it was many years before I can recall ever telling him a published theorem he didn't already know. One day I saw Barry in Princeton shortly after a meeting and told him about an old inequality for PDEs, which, as I could tell from his intent look, was new to him. I said, "It seems to be useful. Do you want to see the proof?" His response "No, that's OK." Then he went to the board and wrote down a flawless proof on the spot.




Ira Herbst


•  Soon after I arrived in Princeton as a postdoc, Barry suggested that we work on proving Borel summability of the perturbation series for the Schwinger functions in two-dimensional \phi^4 quantum field theory. He had an idea which he showed me and after a couple of days I had another idea. But I soon realized that these two ideas were not enough. Up to this time I was a very hard worker but having thought about how ideas percolate up through the subconscious, I decided to relax and let them do just that. WRONG! A couple of weeks later a preprint arrived from Geneva with a proof. 

 Barry, Yosi Avron and I were working on magnetic fields. As everyone knows Barry is a very fast worker and he writes up his work even faster. Barry and Yosi felt we should write something and as usual I wanted to get more done first. One day the two of them arrived in my office and began trying to convince me again that we should write something up.  I protested, at which point Barry took his hand from behind his back and with a smile produced a manuscript which he had presumably written the night before.




Robert Israel


Here are two pictures I took at the 1974 International Congress of Mathematicians in Vancouver.
Barry with Gerry Folland

Barry, Rivka, and Martha




Sergey Khrushchev


Barry explains Szegö recursion
(taken in Snowbird, Utah, June 11, 2003)



Abel Klein


I gave a seminar at Caltech in 1988, I think, on my work with Dreifus on the multiscale analysis, which we had just finished. The title of the talk was "Localization without tears". If my memory is correct, Tom Spencer was visiting Caltech and was at the seminar.

At the end of the seminar, Barry told me that my title was misleading. The Fröhlich-Spencer multiscale analysis had left the feeling of a root canal, but after my talk he still felt like he had been to the dentist.





Woody Leonhard


Many of you know Barry from his academic work and community achievements. I have a rather, uh, different perspective. I had the distinct honor and privilege of co-writing a handful of computer books with Barry, including several Mother of All Windows books, and The Mother of All PC Books.

I’ll never forget Barry’s squeals of delight when he found foolish inconsistencies in Windows, the way his voice would drop low – and he’d talk fast – when he was working through a particularly snarly problem, and the way he’d rub his hands with glee when a solution suddenly appeared.

Barry wrote about PCs with extraordinary clarity and wit. The Mother books became (in)famous for their casts of characters – no dry technical mumbo-jumbo here. My favorite character from the early Mother books was the eight-legged cockroach (and bug expert) known as Erwin. We gave Erwin the enviable assignment of pinpointing and explaining bugs in Windows, a task for which he was eminently qualified.

Barry describes Erwin’s birth this way (icon and quote from "The Mother of All Windows 95" book), from the perspective of uber-iconic Mom, the Mother of the Mother books, as it were:

Erwin has been with me since my first book, pointing out bugs and warning folks about the unthinkable. He’s a dashing eight-legged refuge from the 1930s. The physicists in the audience will no doubt recall Erwin Schrödinger, one of the founders of quantum mechanics, who invented a famous "thought experiment" in which a vial of poison gas might (or might not) kill a cat. Schrödinger’s cat became justly famous among the psi-squared crowd. A few years ago, a computer book writer had the temerity to refer to Schrödinger’s cat in a book submitted to IBM. The IBM Thought Police wouldn’t put up with such an offensive allusion to a cuddly animal, so they changed the manuscript, exorcising Schrödinger’s cat and introducing in his stead Schrödinger’s cockroach, an animal that could be (presumably) sometimes-dead without offending the more delicate readers of IBM manuals.

Barry’s one of the most intensely intelligent people I’ve ever met – and delightful, in every sense of the term. Except for the puns. The puns were really, really bad.

Hey, Barry! Wanna write another Windows book? NO! Put DOWN that brickbat!




Doron Lubinsky


In November 2004, a conference celebrating Ed Saff's 60th Birthday was held at Georgia Tech. Barry Simon, fresh from establishing the first Szego-type conditions for orthogonal polynomials since Szego himself, was a principal invited speaker. On the way to the conference Barry fell ill, and had to spend most of the conference in an Atlanta Hospital. He ate the conference dinner in that hospital — but in the last hours of the conference was able to come to Tech, and to discuss orthogonal polynomials with remaining delegates, presenting some of his talk too.

The slides for Barry's talk were placed on the conference website — and true to form, the very first paper submitted to the proceedings was an excellent one from Barry Simon.


Krishna Maddaly


We were pleased that Barry attended our workshop on
spectral and inverse spectral problems for Schrödinger operators in
Goa, India, in December 2000.  – Peter Hislop and M. Krishna




Edward Nelson


 In the late 1960s, Barry was a graduate student in physics at Princeton and attended some courses I taught. I soon learned that I did not need to prepare with great thoroughness; it was enough to get things approximately right and Barry from where he was sitting would tell us how to get them precisely right. I miss Barry.

 Once Barry was engaged in an acerbic priority dispute with someone at another institution. I offered to intervene, but Barry said, verbatim, "This is my cross to bear.'' (I told this story at a meeting in June 2004 and Barry said mildly, "I would never have said such a thing!'')

 Once Barry wrote a paper on hypercontractive semigroups and when he got it back from the typist, every instance of "hypercontractive'' was rendered as "hypercontraceptive''.

 Barry received an ugly, uncivil letter from a mathematician complaining that he had not been given sufficient credit in a volume of Reed-Simon for his work on a certain topic. Barry responded with a dispassionate two-page letter calmly reviewing the entire history of the topic and the contribution of each person to it. He concluded the letter with a one-sentence paragraph: "I hope that you will receive this letter in the same spirit in which you sent yours.''

•  Shortly after moving to Caltech Barry came east for a visit. He said that someone had stolen his attaché case. When we asked whether he had lost anything of importance, he replied, "Only the paper I wrote on the flight.''

 One Saturday afternoon I saw Barry and Martha strolling with the Cappells. It was a different Barry. Gone were the intense energy and concentration, and in their place were peace, calm, and repose. I had a strong and somewhat wistful sense of the Sabbath as a gift.




Vipul Periwal


In his third year at Caltech, Barry taught a graduate class in group representations. There were two undergraduates in the class, Zinovy Reichstein and me. I couldn't get up at 9 am for lectures and Zinovy took beautiful notes. I typically photocopied Zinovy's notes every week prior to doing the homework. One week Zinovy had to be away. Forewarned I showed up in class. Barry walked into class, did a double-take when he spotted me and announced "It's undergraduate number conservation!'' It never bothered Barry that I did not come to lectures, even though I was one of his undergraduate advisees. When I went to graduate school and expressed some dismay at the less than supportive or encouraging attitudes of the faculty, he wrote me long encouraging letters. I don't think I ever understood how someone as busy as he was, with every minute of his time scheduled, could find the time to write such letters.

Many years later, I was an Assistant Professor at Princeton when Barry came to give a talk. I saw him in the corridor as I was on my way to an undergraduate Senior Thesis oral examination. I greeted him and asked him if he recognized me. He remembered me after a little while, and then was amused (I think) when I told him that I was on my way to an undergraduate oral examination, and reminded him of my first oral examination at Caltech in rigorous statistical mechanics, when he asked me to outline Onsager's solution. He started that particular exam by informing me that he had wanted to put a sophomore through a really rigorous oral ever since his own sophomore year.




Peter Perry


As an undergraduate I took Quantum Mechanics from Barry, little knowing that I would later wind up a student. At the same time, I was taking Functional Analysis from Ira Herbst. The Quantum Mechanics course met on Tuesdays and Thursdays and there was a break in the middle of the lecture. One day I had my copy of Methods of Mathematical Physics, Vol. I, Functional Analysis with me. Barry walked up to me during the break and broke into a big smile followed by mock indignation when he saw that I had a copy of Reed-Simon. "Don't read that stuff!" he admonished me. "It'll pollute your mind! It's worse than comic books!" Long before Barry became a department chair he was already a master recruiter. Several years later, I had the good fortune to begin thesis work with Barry as a graduate student.




Mason Porter


My first encounter with Barry Simon was as a TA at Caltech in fall 1996 when I was a junior. Caltech's core curriculum had just changed, and this was the first year of the new Math 1. Barry was teaching Math 1a out of lecture notes he had prepared instead of the traditional book "Tommy I" (Apostol, Vol. I for those who don't know Caltech lingo).

As an undergraduate living in the Houses (dorms) among the students taking the course, I was privy to blunter comments that other TAs might not be. (These are left as an exercise for the diligent reader.) This ultimately led to a prank by several freshmen from Lloyd House in which "Barry Simon loves you" posters showed up all around campus. I think it was right before finals' week, and he was dressed appropriately as Santa Claus. (This may have actually been fall 1997. Barry taught Math 1a again that year.) If I remember correctly, I think that the posters made some sort of comment about "He's reading your proofs and checking them twice." I'm not sure if Barry appreciated it, but I thought it was pretty funny.

Postscript: I took Barry Simon for Math 110a (complex analysis) in fall 1997. After hearing my fellow undergrads complain all quarter (in 2 different years), I have to admit I was worried about how things would go. Despite these concerns, I found that Barry did a very good job and thought that was a very nice class.

Postscript II: When I taught Math 1d in spring 1997, I have the understanding that Barry was responsible for an extra $500 I received in my salary at the 11th hour. As an undergrad going to a private school, I was really poor and appreciated that quite a bit.




Grigori Rozenblum


A funny typo I saw in a paper by Barry. In Phys. Rev. Letters, vol. 65,  no. 17 (1990), 2185-2188, in the reference to a paper published in Trans. AMS, the latter society was spelled as Am. Microsc. Soc.




Beth Ruskai


After he moved to Caltech, Barry invited me to spend a month there, which, I think, ended up as April, 1984. Since e-mail was not yet widely used, he phoned me in February to arrange times for us to talk before his schedule filled up.

While I was there, I sat in on some of his lectures. One day he wrote a bound on the board and claimed it followed from the Schwarz inequality. I interrupted and said that was not true. He stopped, said "You're right", paused about 10 seconds and proceeded to give a different, correct proof of the desired bound. He did this so quickly, that I assumed the second argument was what he'd prepared and the first was the kind of blackboard glitch I often make. Later I learned that the incorrect Schwarz claim was in his Trace Ideals book, and he'd come up with a different argument on the spot.

The AMS recently issued a second edition of the Trace Ideals book. At the meeting in San Antonio, I looked in the new version, but couldn't find the error any more. So the younger generation will have to go to the library to see that even Barry makes mistakes.




Lorenzo Sadun


Barry always enjoyed a good (or bad) prank. Jan Segert, Yosi Avron, Barry and I wrote a paper on nonabelian Berry's phase. Since there was already a table of contents, Jan added the abstract: "Yes, but some parts are reasonably concrete". CMP accepted the paper, but insisted on a "serious" abstract. Jan, our corresponding author, complied, but when Barry found out, he was furious. "The abstract is the best part of the paper! Tell them we won't publish the paper without it." I'm not sure if he intervened with CMP, or if he insisted that Jan do so, but the original abstract got published.




Barry Simon


The stories here have reminded me of some of my own. When Mike Reed and I got the page proofs for Volume 1, we found some really amazing typos (recall in those days that rather than working from a submitted TeX file, one sent in a typed manuscript and a typesetter reentered everything on a fancy machine): the proofs referred to "the nationalized Planck's constant" and to the "night shift operator." I recall Mike joking that perhaps the latter had been entered by the night shift guy who was trying to enter what we'd now call an Easter Egg.

To improve the exposition, Mike and I would read the manuscript aloud to each other. It sounds silly but it really worked well. At one point in the manuscript of a later volume, we had the phrase "the reader can convince himself." We realized that was sexist and toyed with "him or herself" but decided that sounded bad. So we finally settled on "the reader can convince herself" which is how it appears. When we got the page proofs back, besides proofreading it ourselves, we doled out the typescript to various postdocs to look at. One, who will remain nameless but who was less than liberated, walked into my office: "You won't believe it — I found the funniest typo..." I assured him it was not a typo but done on purpose. He argued with me that we had to change it, but I was insistent that we wouldn't. He finally sputtered, "But no girl is going to read this book."

Speaking of Reed-Simon, Mike visited NYU at one point and at tea was introduced by Peter Lax to a graduate student as Mike Reed, the coauthor of Reed-Simon. The student looked shocked and exclaimed: "You're Reed? I thought Reed was Simon's first name."

Finally, here is the end of Lorenzo's story. As background, I have to mention that the in-house Springer editor for CMP, Dr. Wolf Beiglbock, is also the editor of the Springer series, Texts and Monographs in Physics, where my book with Cycon et al. appeared. Because I felt much of the book's audience is mathematicians, I had some reluctance signing with this series and only did so when Beiglbock promised me it would be included in the Springer Yellow Sheet mailing of mathematics books that went out broadly in the U.S. In the end, he tried to have it done but failed and we exchanged some rather heated words at a conference the summer before the paper of Avron, Seigert, Simon, and Sadun was written.

I was indeed angry when Jan informed me that he'd returned the manuscript with an abstract included. This was before email attachments,  so he'd put the manuscript in the mail. We Fedexed a copy of the manuscript with all the corrections in except with the original "abstract but some parts are concrete" back in place. We included a cover letter saying that we had discovered a terrible error in the manuscript we'd mailed in earlier that day and CMP should ignore the mailed copy and use this.

Arthur Jaffe was the editor-in-chief of CMP at the time and his secretary, Barbara Drauschke, is a bright lady. We knew each other well because I was an editor myself. Several weeks later she phoned saying that so far as she could tell, the only difference between the two versions we'd sent in was the abstracts and she would use the "real abstract." I said that we were the authors and did not authorize the use of any other abstract but the one we had Fedexed. She replied: "Well, even if Professor Jaffe is willing to allow it, there is no way he'll get Dr. Beiglbock's approval." Remembering that I felt Beiglbock "owed me one" I said: "Tell Arthur to tell Beiglbock to call me if he has any problem." I never got a call and the abstract appeared in the form we wanted.




Rick Simon


I have enjoyed reading all of the Barry stories from his colleagues. Some of you have known Barry for almost 40 years. I know him a little longer – for almost 60 years! Most of you know Barry from his substantial academic achievements. Like Woody Leonhard, I know Barry from a different perspective. I found several pictures of him that I would like to share with all of you, together with a couple of Barry Stories:


 When we were growing up in Brooklyn, we had a cleaning woman who cleaned our apartment once a week. Betty always said that everything Barry knew he learned from his older brother.  Oh, how I loved that woman.


 When Barry was a senior in high school, he took a Nation-Wide Math exam sponsored by the Mathematics Association of America and the Society of Actuaries. Believe it or not he got one wrong answer. Well, Barry didn’t believe it either. So he appealed claiming that due to the ambiguous wording of the question that he “missed”, there were actually two possible correct answers. Barry’s appeal was granted and he became the fifth student in the thirteen-year history of the exam to achieve a perfect score. This accomplishment resulted in a feature article entitled: “One Student Plus One Challenge Equals One Perfect Math Score” that appeared on the first page of the second section of the May 2, 1962 edition of The New York Times. The complete article follows:


A senior at James Madison High School in Brooklyn has become the second student here to make a perfect score this year on the nation-wide examination sponsored by the Mathematics Association of America and the Society of Actuaries.

Barry M. Simon, 16 years old, of 2410 Kings Highway, received a score of 143.75 out of a possible 150 on the test, which was given on March 8. In an appeal to the committee on contests and awards, he pointed out that because of the ambiguous wording of the question he had "missed" there were actually two possible correct answers.

Prof. Charles T. Salkind of Polytechnic Institute of Brooklyn, chairman of the committee, wrote Barry that his appeal had been granted and that he had received a  perfect score.

Fifth To Get Score

Barry thus became the fifth student in the thirteen-year history of the examination to score a perfect 150. Last month it was announced that Michael Razar, 16, of 73-37 Austin Street, Forest Hills, Queens, had received a perfect score. Michael is a student at Forest Hills High School.


The question and choices on which Barry based his appeal read as follows.

     36. If both x and y are integers, how many pairs of solutions are there of the equation (x–8) (x–10) = 2y?
0  (b) 1  (c) 2  (d) 3  (e) more than 3

Solving the equation, Barry found two answers:  x = 12, y = 3 and x = 6, y = 3. Reasoning that two solutions to the equation made up one pair of solutions, he selected answer (b), which was marked incorrect.

Barry pointed out that an answer giving the values of both x and y is sometimes called a solution pair. But since the question asked for pairs of solutions, he maintained successfully that his answer was valid.

Barry's high school average is a little over 96, and he is fourth in his graduating class of 750 students. He was accepted for admission by Harvard, Massachusetts Institute of Technology, California Institute of Technology, Columbia University and Brooklyn College, and has decided to enter Harvard next fall to major in physics. He was awarded an honorary scholarship and is considering a career in college teaching.

Father Accountant

"I've always liked science and math," Barry said in an interview, "but I can't remember anything special that aroused my interest." A bridge "addict" since he learned to play at the age of 10, he participates in weekly duplicate bridge tournaments with his father as his partner.

Mr. Simon is a registered public accountant and a supervisor in the Post Office. Barry's mother teaches a fourth-grade class of intellectually gifted children at Public School 169, Brooklyn.

Barry is the captain of the Madison High Math Team and editor in chief of the school's Math and Science magazine. For three years he has attended Columbia University's Saturday Science Honors Program for outstanding high school students, where he is currently doing work in group theory, vector analysis and computer programming.

Last summer he attended the National Science Foundation Summer Institute at Cooper Union, where his brother is studying mechanical engineering. This year Barry won an honorable mention in the nation-wide Westinghouse Science Talent Search with a project in pure mathematics.


I look forward to meeting many of you at SimonFest 2006.  Even though I will not understand a word of the technical presentations, I hope that some of the speakers will do a little roasting…something that Barry well deserves.


The Simon Family:  Hy, Minnie, Barry, and Rick (ca 1959)


(ca 1953)                                  (ca 1947)





Yakov Sinai


In the mid-1970's, Barry visited Moscow. One day he went into a store to buy some eggs. He handed over a 10 ruble bill to the storekeeper and said "Eggs" in Russian; it was the only word in Russian which he knew. She asked him whether he wanted to spend all 10 rubles (a considerable amount in those days) on eggs. But this was a different phrase which Barry didn't understand, and in reply he just smiled his charming smile. She then gave him a check for a hundred eggs.

The following day, Barry gave a seminar at the university. It was his last day since he was leaving Moscow the next day. After his talk, he distributed the eggs among the participants. Following the American tradition, undergrads and graduate students received the largest number of eggs and professors received almost nothing.



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