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.

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.

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