In Memoriam: John “Ernie” Esser

John “Ernie” Esser died Sunday, 8 March 2015, at a hospital in Reykjavik, Iceland, of complications from the flu and pneumonia, which he suffered on a flight home from Europe.

Ernie was a mathematician who grew up in Bothell and graduated from the University of Washington and UCLA. He was born May 19, 1980, in Seattle, the day after Mount St. Helens erupted. Ernie attended Northshore schools and graduated from UW in 2003 with degrees in math, applied math, and Italian, the native language of his mother.

Ernie earned his mathematics Ph.D. from UCLA in 2010 and did postdoctoral research at the University of California Irvine until 2013. He was currently working as a postdoctoral fellow at the Seismic Laboratory for Imaging and Modelling (SLIM) at the University of British Columbia.

Ernie is survived by his parents, Doug and Rita Esser of Bothell, his brother Mike of Bellevue, uncles, aunts, and cousins. He had countless friends.

SLIM Lab director Felix J. Herrmann said Ernie “was a fantastic researcher working on a wide variety of problems ranging from full-waveform inversion to blind-deconvolution. Ernie was an extremely enthusiastic and extremely talented researcher who was, above all, immensely generous with his time and ideas.”

His friend Samuel Coskey said, “But what made Ernie exceptional to me was that he was never, ever, mean or nasty or cynical about anything. Period. He was always saying things that make you feel good.”

Ernie liked everywhere, played soccer, hiked, flew boomerangs, and made wine and mead to share with friends.

He maintained close ties with his UW mentor, math Professor James Allen Morrow, and returned each spring to conduct a “Why boomerangs come back”

presentation at the UW Math Day program for high school students.

Remembrances may be made to support Math Day here.

In memoriam: Herbert B. Enderton Professor of Mathematics, Emeritus, 1936 – 2010

Adjunct Professor Emeritus Herbert B. Enderton died at his home in Santa Monica on October 22, 2010, after battling leukemia for nearly a year. Enderton received his Ph.D. in mathematics in 1962 at Harvard University under the supervision of Hilary Putnam. He had a postdoctoral appointment at MIT from 1962 to 1964, and he was an assistant professor at UC Berkeley from 1964 to 1968. In 1968 he came to UCLA, where he took on two half-time positions, one in the mathematics department and the other as an editor of the reviews section of the Journal of Symbolic Logic. In 1980 the latter job became a more important one when he was made the coordinating editor of the reviews section. As such he was in charge of a major function of the Association for Symbolic Logic, and he remained in this role until 2002. Enderton retired from the department in 2003, but he continued to teach regularly until he became ill in 2009. He similarly continued being in charge of the UCLA Logic Colloquium, as he had been for decades.

Enderton’s thesis and the majority of his published research were on recursion theoretic hierarchies of sets of integers. This subject, which Enderton characterized as “little steps for little feet,” was a very active part of mathematical logic in the 1950s, 1960s, and 1970s, and Enderton was a major contributor to it. In the early 1970s, he began devoting himself to teaching, writing expository articles, and—with great success—writing textbooks. His first book, A Mathematical Introduction to Logic, was published in 1972. It is the most popular logic text at the advanced undergraduate/beginning graduate level, and it is often used (especially by computer scientists) as “the” standard reference to logic. It is still going strong in its second edition, published in 2001. Spanish and Chinese translations appeared in 2004 and 2006 respectively. His 1977 Elements of Set Theory has also been very successful. A new undergraduate text, Computability Theory: an Introduction to Recursion Theory, was completed after he had become ill and was published in 2011.

Herb Enderton was an active participant in the life of the logic group at UCLA, and he will be sorely missed. He is survived by his wife Catherine, his sons Eric and Herbert (“Bert”), and his granddaughter Evelyn.

In Memoriam: Heinz-Otto Kreiss

The department is sad to announce that Professor Emeritus Heinz-Otto Kreiss, passed away on Wednesday, December 16th. He died peacefully in his home without pain or anxiety. 

Heinz-Otto Kreiss

1930-2015

One of the great figures in numerical analysis and applied partial differential equations passed away on December 16, 2015, at his home in Stockholm.  Heinz, as everyone called him, was a faculty member in the Department from 1987-2001 but this fact understates his influence on UCLA’s Applied Mathematics Group.

He was born in Hamburg, Germany, lived and worked on a farm during the war, and became an undergraduate in Hamburg in 1950.  In 1955 he went to Stockholm, Sweden where he began his stellar research career.  He was a Professor at the Chalmers Institute of Technology in Gothenberg from 1964-65, Uppsala University from 1965-78, Caltech from 1978-1987, and here from 1987-2001, when he retired and returned to Sweden.

Heinz visited the Courant Institute in the 60s quite often and I was lucky enough to meet him in 1966.  This meeting changed my research direction.  He had just proven the stability of finite difference approximations to hyperbolic equations in one space dimension with the appropriate numerical boundary conditions. I then came up with an elegant proof involving Toeplitz matrices after reading his paper.  This got me a job at UC Berkeley and started my career in applied mathematics.

Heinz was a terrific, no-nonsense mathematician, with an uncanny ability to get sharp estimates, usually involving families of matrices depending on parameters.  There is the Kreiss matrix theorem, stability of difference approximation to hyperbolic equations, well-posedness of initial-boundary value problems for these equations, problems with different time scales, many results on numerical weather prediction and atmospheric science in general, and analysis of incompressible Navier-Stokes equation, to name a few of his contributions.

He was also a wonderful and caring human being, who was totally unpretentious (which is not the usual image of a stuffy European professor).  For example, when he was inducted into the Swedish Academy of Sciences, the story goes that he had to borrow a tie and sport jacket from a waiter to get into his dinner and reception.  Past and present UCLA faculty members who were influenced by his work include his Ph.D. student Bjorn Engquist, Andrew Majda, Daniel Michelson, Gregory Eskin, James Ralston, Eitan Tadmor, Moshe Goldberg, and myself. 

Heinz generated mathematical excitement and enthusiasm and had a charmingly cynical edge at times.  He was always fun to be around.   He loved his island retreat in Sweden, hated doing university administration, and had an equally wonderful life partner in his wife Barbro, who we all got to know well.  His daughter Gunilla is now a Professor in Numerical Analysis at Uppsala University.  His scientific legacy lives on.  According to the Mathematics Genealogy Project, he has 26 students and 463 descendants.

He will be missed by everyone who knew him.  He was great, both as a scientist and as a human being.

Professor Stanley Osher

In Memoriam: Greg Hjorth, Professor of Mathematics, 1963 – 2011

Professor Greg Hjorth died of a heart attack in his birth city of Melbourne, Australia, on Jan. 13. He was 47. Hjorth was recognized as a young chess whiz in his primary school years. He quickly advanced to tournament chess, becoming joint Commonwealth Champion in 1983 and earning his International Master title in 1984. He played Garry Kasparov, among other accomplished chess rivals, but took his own later advice that “if you’re not in the top 100 by 21, get out.” Hjorth’s passion for chess played over to mathematical logic, a field that saw him reach great heights with high academic honors and wide recognition. After receiving his undergraduate degree in mathematics and philosophy at the University of Melbourne, Hjorth continued his studies at UC Berkeley, where he received his Ph.D. in mathematics under the supervision of Hugh Woodin in 1993. As a graduate student, Hjorth was recognized for his exceptional talent, and his brilliant thesis was awarded the first Sacks Prize in 1994 by the Association for Symbolic Logic for his research in descriptive set theory and its surprising consequences concerning the relationship between projective sets and large cardinals. Hjorth pursued his postdoctoral studies at Caltech for two years then joined the mathematics faculty at UCLA in 1995, where he was made full professor in 2001. Since 2006, he spent two quarters of each year at the University of Melbourne appointed to a prestigious Australian Research Council professorial fellowship.

Over his 16 years at UCLA, Hjorth has been acknowledged as a world leader in the field of mathematical logic and its applications to other fields of mathematics. He has made a series of stunning and far-reaching contributions, in particular to ergodic theory and orbit equivalence of group actions. These included the development of entirely new theories, including what is now called Hjorth’s theory of turbulence, which has had a major impact on contemporary work in set theory and its applications. Hjorth was known as a brilliant problem solver, having been able to achieve major breakthroughs in problems that were previously considered intractable, including his remarkable work on the famous topological Vaught Conjecture and most recently, his results on the incomparability of treeable equivalence relations. His work consistently amazed his colleagues with its uncanny originality and technical wizardry and has been recognized by many honors, including a Sloan Foundation Fellowship in 1997, an invited lecture at the International Congress of Mathematicians in 1998, the ASL Karp Prize in 2003 (joint with Alexander Kechris), and last year, an invitation to deliver one of the major lecture series in logic, the Alfred Tarski Lectures at UC Berkeley. Hjorth supervised eight Ph.D. students at UCLA, including the 2008 UCLA Math Ph.D. Inessa Epstein, who also received the prestigious Sacks prize.

Hjorth will be richly remembered by fellow colleagues as a brilliant mathematician in constant pursuit of solutions to intractable problems, and as a committed and caring teacher. He is survived by his parents Noela and Robert, and his sister Larissa. 

In Memoriam: Geoffrey Mess

Geoffrey Mess, a mathematics professor at UCLA, died on August 8th, 2014.

Following the completion of a brilliant Ph.D. thesis at UC Berkeley on Torelli subgroups of mapping class groups, Geoffrey Mess joined the UCLA Mathematics Department as a Hedrick Assistant Professor, a visiting position reserved for top young PhDs from around the world.  He joined the regular faculty in 1988 as an Assistant Professor. He rose to prominence in the areas of topology and geometric group theory by making a number of deep contributions to these fields.  He laid the basis for the solution of the Seifert conjecture by Casson and Gabai. His joint work with Bestvina on torsion-free Gromov hyperbolic groups has produced what is now known as the Bestvina-Mess formula relating the cohomological dimension of such a group to that of its boundary. Another of his celebrated results, on symmetries of Lorentz spacetimes of constant curvature, is a theorem that bears his name.  Mess was awarded a Sloan research fellowship in 1990, and promoted to Associate Professor in 1992.  He left a legacy of seven graduate students who have completed their PhDs under his supervision at UCLA: Emily Hamilton (1995), Iakovos Iliadis (1994), Havrenik Mherian (1990), Maria Morrill (1996), Eleanor Rieffel (1993), Kevin Scannell (1996) and William Sherman (1993).  

Geoffrey Mess was born in Montreal on February 19th, 1960 to Annette and David Mess.  He entered the University of Waterloo at age 16, graduating with a Bachelor’s in Mathematics in 1980.  Geoff’s doctoral thesis was supervised by Andrew J. Casson and John R. Stallings, Jr. Geoff leaves behind a brother, Derek Mess, and a nephew, Dylan Mess, both of Cambridge, MA.

Beyond mathematics, Geoff’s interests included physics, world history, languages, kayaking, hiking, and backpacking. He hiked Vermont’s Long Trail, as well as hundreds of miles in the Sawtooth Mountains and the Canadian Rockies.

Geoffrey Mess battled illness for much of the past 20 years.  The illness stole away his research productivity first and then succeeded in stealing him from us.  He will be remembered and missed.

View Goeffrey Mess’ Full Obituary in the Daily Bruin here.

In Memoriam: David G. Cantor, Professor of Mathematics, 1935 – 2012

Professor Emeritus David G. Cantor passed away on November 19, 2012. After completing undergraduate work at the California Institute of Technology in 1956, he received his Ph.D. from UCLA in 1960 under the combined direction of Basil Gordon and Ernst Straus. He held an instructorship at Princeton University (1960-62), followed by an Assistant Professor position at the University of Washington (1962-64).

Professor Cantor came to UCLA in 1964 with an appointment in the Department of Mathematics and a courtesy appointment in the Computer Science Department. Over the years he advised a number of Ph.D. students while also contributing greatly to the development of computing capabilities in the Department of Mathematics. He retired from UCLA in 1991 and thereafter was a researcher at the Center for Communications Research in La Jolla, CA.

His distinction in number theory and combinatorics was recognized by a number of awards, including the (honorary) NSF Postdoctoral Fellowship in 1960 and a Sloan Foundation Fellowship in 1968; and, most recently, by his selection as a Fellow of the American Mathematical Society.

At the time of his passing, he was 77. He will be greatly missed by all who knew him.

Profs. Wotao Yin and Mason Porter named among the most influential researchers in the world

Profs. Yin and Porter

Thirty-seven UCLA scholars have been named as the world’s most influential scientific researcher. This annual list of the most highly cited researchers is compiled by the Institute for Scientific Information at Clarivate using data based on scholarly publication counts and citation indexes. The selected researchers wrote publications that ranked in the top 1% by citations in their field for that year, according to the Web of Science citation index.

Wotao Yin and Mason Porter, applied mathematicians and professors within the Department of Mathematics, have been named among 2020’s UCLA scholars listed. Yin is best known for co-inventing fast algorithms for sparse optimization and distributed optimization. Currently, he is working on optimization algorithms for noncovex and large-scale problems. Porter works in diverse topics — encompassing theory, computation, and applications — in networks, complex systems, and nonlinear systems.

To read the full UCLA Newsroom article, click here.

In Memoriam: A.V. Balakrishnan

A.V. Balakrishnan, distinguished professor emeritus and research professor of electrical engineering, passed away Tuesday morning, March 17. Bal, as he was known to everyone, was a member of the UCLA faculty for more than 50 years. Bal grew up in Chennai, India. He earned his B.Sc. and an M.A. from the University of Madras. After moving to the U.S., he earned an M.S. in electrical engineering in 1950, and his Ph.D. in mathematics in 1954, both from USC. Following his Ph.D., Bal was a project engineer at the Radio Corporation of America (RCA), taught at USC and UCLA; and was a researcher at Space Technology Laboratories in Redondo Beach. He joined UCLA Engineering at the associate professor level in 1961. Over Bal’s long and distinguished career here, he supervised 54 master’s students; 18 Engineer degree recipients and 54 Ph.D. graduates, many of whom went on to careers in academia and industry. And he was the author of two books. Bal was a teacher and scholar of the highest order. He published singled authored papers while encouraging his students to publish their work under their own names. Twice he served as chair of the Department of Systems Science. He also held an appointment in Mathematics. For several years, he was the director of the Flight Systems Laboratory at UCLA that was supported by NASA. Bal was named a Fellow of IEEE in 1966 and a Life Fellow in 1996. He received the NASA Public Service Medal in 1996; the Richard E. Bellman Award in 2001 from the American Automatic Control Council (AACC) for distinguished achievements in control theory; and the Distinguished Alumni Award in Academia from USC Viterbi in 2004. Bal had a highly distinguished career here at the school, teaching thousands of students stochastic processes, linear systems, and optimal control. He will be missed.