For more information about Paul R. Halmos (1916-2006) and about the Paul R. Halmos Photograph Collection, please see the introduction to this article on page 1. A new page featuring six photographs will be posted at the start of each week during 2012.

Halmos photographed his Ph.D. student Stephen Parrott on September 10, 1964, at the University of Michigan in Ann Arbor. Parrott earned his Ph.D. in 1965 from Michigan with the dissertation “Weighted Translation Operators,” written under Halmos. In his book *I Want to Be a Mathematician: An Automathography* (Springer, 1985), Halmos described how Parrott accidentally broke his (Halmos’) coffee cup and how the incident apparently broke the ice between the two of them and had the happy ending of Parrott becoming his Ph.D. student (pp. 278-279). Parrott spent most of his career on the mathematics faculty at the University of Massachusetts in Boston, from which he is now retired. His interest in operator theory has been replaced more recently with an interest in mathematical physics. (Source: Mathematics Genealogy Project, University of Massachusetts–Boston Mathematics, Stephen Parrott homepage)

Carl Pearcy, left, and Paul Halmos were photographed in 1965. At the time, both Halmos and Pearcy were on the mathematics faculty at the University of Michigan in Ann Arbor. Pearcy earned his Ph.D. in 1960 from Rice University (then the Rice Institute) in Houston, Texas, with the dissertation, “On the Unitary Equivalence of N-Normal Operators.” His thesis advisor at Rice was H. Arlen Brown, who had earned his own Ph.D. from the University of Chicago in 1952 under advisors Paul Halmos and Irving Kaplansky. Another photograph of Pearcy appears on page 29 of this collection, where you can read more about him. (For a photo of Brown, see page 8; Kaplansky’s photo appears on page 26.) (Source: Mathematics Genealogy Project)

Halmos photographed Carl Pearcy in August of 1975, probably at Bucknell University in Lewisburg, Pennsylvania. Besides the two photographs above, another photograph of Pearcy appears on page 29 of this collection, where you can read more about him.

Roger Penrose was photographed by Halmos in April of 1980 in Bloomington, Indiana. Penrose earned his Ph.D. in 1958 from Cambridge University with the dissertation, “Tensor Methods in Algebraic Geometry,” written under John Arthur Todd (not John “Jack” Todd). From 1956 to 1964, he held various fellowships and positions in England and the U.S., from 1964 to 1973 he was on the mathematics faculty at Birkbeck College in London, and from 1973 onward he has been Rouse Ball Professor of Mathematics at Oxford University, emeritus since 1998. He has advised at least 30 Ph.D. students, at least 27 of them at Oxford.

Since his university days (at University College London), Penrose has been interested in both pure and applied mathematics and in physics, and his best known results throughout his career have been in geometry and mathematical physics. In awarding him its Copley Prize in 2008, the Royal Society cited his breakthroughs in gravitation theory, his application of spinors and twistors to space-time, his non-periodic Penrose tilings, and his popular books relating mathematics, physics, and cognition. Sir Roger Penrose has won numerous scientific awards and was knighted by the Queen of England in 1994. (Sources: MacTutor Archive, Mathematics Genealogy Project)

Klaus Peters (1937-2014), left, and Paul Halmos were photographed on July 19, 1968, in Oberwolfach, Germany, where the two were attending a conference at the Oberwolfach Conference Center. This conference was one of a series of seven organized by Paul Butzer (page 9) from 1963 to 1983 on approximation theory and related topics in functional analysis. The 1968 conference was the first of the three Halmos attended.

Peters earned his doctoral degree (Dr. rer. nat.) in complex analysis from the University of Erlangen-Nürnberg in 1962 under advisors Reinhold Remmert (see page 18 of this collection) and Georg Nöbeling. Peters began his career as a mathematics professor but, within two years, had taken a “temporary” position as a mathematics editor at Springer Verlag. During his 1964-1979 tenure at Springer, he increased mathematical publications from 5 books per year to over 100 books per year. In 1979, he and his wife Alice Peters founded Birkhauser Boston, which they sold to Springer in 1984. They then opened the Cambridge, Massachusetts, offices of Academic Press / Harcourt Brace Jovanovich, and took over that company’s publications in mathematics, computer science, and theoretical physics. In 1992, Alice and Klaus Peters founded A K Peters Ltd., Publishers of Science and Technology; in 2010, they sold their company to the Taylor and Francis Group, which made it part of CRC Press. (Sources: Mathematics Genealogy Project, A K Peters Publishers)

Klaus Peters recently (Oct. 2012) shared a story typifying “Paul’s practical and insightful perception”: He recalled telling Halmos “on a walk in the hills above Santa Clara in 1978, before anybody knew” that he and Alice were going to leave Springer Verlag in order to .... Before he could share their plans, Halmos “asked for half an hour ‘time out’ by the end of which he would tell me our next move. Then, he correctly predicted that we would start the American affiliate of Birkhäuser Verlag. He was right and provided a clear and rational explanation.”

Halmos photographed Klaus Peters on January 23, 1970, at the Joint Mathematics Meetings in San Antonio, Texas. Peters is pictured at the Book Exhibit, of course!

For an introduction to this article and to the Paul R. Halmos Photograph Collection, please see page 1. Watch for a new page featuring six new photographs each week during 2012.

**Regarding sources for this page:** Information for which a source is not given either appeared on the reverse side of the photograph or was obtained from various sources during 2011-12 by archivist Carol Mead of the Archives of American Mathematics, Dolph Briscoe Center for American History, University of Texas, Austin.