20th-century American mathematicians

Carl Mark Pearcy, Jr. (born August 25, 1935) is an American mathematician whose research has been concentrated on operator theory and operator algebras. He has coauthored several books, including "Introduction to Operator Theory I", Introduction to Analysis", and "Measure and integration", all published by Springer and coauthored by Arlen Brown (and Hari Bercovici in the case of Measure and integration). Pearcy had 31 Ph. D. students at Michigan and TAMU
, several of whom are outstanding mathematicians. Pearcy's bibliography contains more than 150 papers, and his research has concerned the invariant subspace problem and the theory of dual algebras.

Robert Lawson Vaught (April 4, 1926 – April 2, 2002) was a mathematical logician and one of the founders of model theory.

George Rushing Kempf (Globe, Arizona, August 12, 1944 – Lawrence, Kansas, July 16, 2002) was a mathematician who worked on algebraic geometry, who proved the Riemann–Kempf singularity theorem, the Kempf–Ness theorem, the Kempf vanishing theorem, and who introduced Kempf varieties.

Morton Landers Curtis (November 11, 1921 – February 4, 1989) was an American mathematician, an expert on group theory and the W. L. Moody, Jr. Professor of Mathematics at Rice University.Born in Texas, Curtis earned a bachelor's degree in 1948 from Texas A&I University, and received his Ph.D. in 1951 from the University of Michigan under the supervision of Raymond Louis Wilder. Subsequently, he taught mathematics at Florida State University before moving to Rice. At Rice, he was the Ph.D. advisor of well-known mathematician John Morgan.Curtis is, with James J. Andrews, the namesake of the Andrews–Curtis conjecture concerning Nielsen transformations of balanced group presentations. Andrews and Curtis formulated the conjecture in a 1965 paper; it remains open. Together with Gustav A. Hedlund and Roger Lyndon, he proved the Curtis–Hedlund–Lyndon theorem characterizing cellular automata as being defined by continuous equivariant functions on a shift space.Curtis was the author of two books, Matrix Groups (Springer-Verlag, 1979), and Abstract Linear Algebra (Springer-Verlag, 1990).

Halsey Lawrence Royden, Jr. (September 26, 1928 – August 22, 1993) was an American mathematician, specializing in complex analysis on Riemann surfaces, several complex variables, and complex differential geometry. Royden is the author of a popular textbook on real analysis.

Abraham Sinkov (August 22, 1907 – January 19, 1998) was a US cryptanalyst. An early employee of the U.S. Army's Signal Intelligence Service, he held several leadership positions during World War II, transitioning to the new National Security Agency after the war, where he became a deputy director. After retiring in 1962, he taught mathematics at Arizona State University.

Louis de Branges de Bourcia (born August 21, 1932) is a French-American mathematician. He was the Edward C. Elliott Distinguished Professor of Mathematics at Purdue University in West Lafayette, Indiana, retiring in 2023. He is best known for proving the long-standing Bieberbach conjecture in 1984, now called de Branges's theorem. He claims to have proved several important conjectures in mathematics, including the generalized Riemann hypothesis.
Born to American parents who lived in Paris, de Branges moved to the US in 1941 with his mother and sisters. His native language is French. He did his undergraduate studies at the Massachusetts Institute of Technology (1949–53), and received a PhD in mathematics from Cornell University (1953–57). His advisors were Wolfgang Fuchs and then-future Purdue colleague Harry Pollard. He spent two years (1959–60) at the Institute for Advanced Study and another two (1961–62) at the Courant Institute of Mathematical Sciences. He was appointed to Purdue in 1962.
An analyst, de Branges has made incursions into real, functional, complex, harmonic (Fourier) and Diophantine analyses. As far as particular techniques and approaches are concerned, he is an expert in spectral and operator theories.

Alice Turner Schafer (June 18, 1915 – September 27, 2009) was an American mathematician. She was one of the founding members of the Association for Women in Mathematics in 1971.

Ronald George Douglas (December 10, 1938 – February 27, 2018) was an American mathematician, best known for his work on operator theory and operator algebras.

Margaret Kampschaefer Butler (March 27, 1924 – March 8, 2013) was a mathematician who participated in creating and updating computer software. During the early 1950s, Butler contributed to the development of early computers. Butler was the first female fellow at the American Nuclear Society and director of the National Energy Software Center at Argonne. Butler held leadership positions within multiple scientific organizations and women's groups. She was the creator and director of the National Energy Software Center. Here, Butler operated an exchange for the editing of computer programs in regards to nuclear power and developed early principles for computer technology.