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.

Maurice Auslander (1926-1994) at Indiana University, Bloomington, where Paul Halmos was a faculty member from 1969 to 1985, on Feb. 18, 1974. By this time, Auslander was working on representation theory of Artin algebras and we imagine that he may have given a talk on this topic at Indiana University. Auslander spent his career at Brandeis University in Waltham, Massachusetts, but frequently held visiting positions elsewhere (MacTutor History of Mathematics Archive).

Two views of Reinhold Baer (1902-1979) at a conference at the Oberwolfach Institute in Germany on July 22, 1968. At left, he is with his wife, Marianne Baer, and below, he seems to have been interrupted by the photographer while reading. Baer was a group theorist who advised at least 59 Ph.D. students at the University of Illinois, Urbana-Champaign, from 1938 to 1956 and at Goethe Universität Frankfurt am Main from 1956 onward (MacTutor History of Mathematics Archive, Mathematics Genealogy Project). He and Halmos would have met in 1938, the year Halmos earned his Ph.D. at the University of Illinois and the year Baer joined the faculty there. They would have overlapped because Halmos remained at Illinois as an instructor during 1938-1939 (MacTutor History of Mathematics).

Thomas Banchoff lectures at Indiana University in Bloomington, Indiana, on Oct. 27, 1975. Banchoff has been a faculty member at Brown University in Providence, Rhode Island, since 1967, where he has specialized in geometry and in computer graphics to help visualize geometry (MAA Presidents). Indeed, he may be best known for his work on visualizing the fourth dimension. Banchoff served as president of the Mathematical Association of America (MAA) during 1999-2000 (MAA Presidents).

From left to right, Charles N. Moore, Fannie R. Barnett, Isaac A. Barnett, and Paul Erdös (1913-1996) enjoy a gathering in 1958 in ... Chicago? Cincinnati? Charles Napolean Moore (1882-1967) earned his Ph.D. in analysis under Maxime Bôcher at Harvard in 1908 and had at least 17 Ph.D. students of his own during a career at the University of Cincinnati, Ohio (Ohio Masters of Mathematics, Mathematics Genealogy Project). Isaac Albert Barnett (1894-1974), earned his Ph.D. in differential equations under Gilbert Bliss at the University of Chicago in 1918, and, like Moore, was a faculty member at the University of Cincinnati. The University of Cincinnati established a lecture series in number theory in honor of Isaac and Fannie Barnett (Ohio Masters of Mathematics). Paul Erdös, the well known itinerant polymath, was famous for posing and solving problems all over the world and with all sorts of mathematical partners. In 1958, Halmos was a faculty member at the University of Chicago, and our best guesses as to the location of this photograph would be Chicago or Cincinnati. On the back of the photograph, Halmos wrote only “C. N. Moore, Barnett’s, Erdös” and there is a stamp showing the photo was printed on Sept. 30, 1958.

Lida Barrett was photographed by Halmos during the winter of 1981. Barrett moved from her position as mathematics department chair at the University of Tennessee, where she had worked in topology and applied mathematics, to an administrative position at Northern Illinois University in 1980, and this photo probably was taken in Illinois or Indiana. She would continue her administrative career at Mississippi State University and the National Science Foundation and her teaching career at the United States Military Academy, West Point, New York. Barrett has served the MAA throughout her career, including leading the MAA as president in 1989-1990 (MAA Presidents).

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.

**Sources:**

- Archives for American Mathematics, Dolph Briscoe Center for American History, University of Texas, Austin. Information for which a source is neither cited nor given in this list either appeared on the reverse side of the photograph or was obtained by AAM archivist Carol Mead from various sources during 2011-12.
- MacTutor History of Mathematics Archive, St. Andrews University, Scotland (Maurice Auslander, Reinhold Baer, Paul Erdös)
- Mathematical Association of America Presidents (Thomas Banchoff, Lida Barrett)
- Mathematics Genealogy Project, North Dakota State University (all mathematicians)
- Ohio Masters of Mathematics, Bowling Green State University (Charles Moore, Fannie Barnett, Isaac Barnett)