A murder mystery in which the victim is a female math grad student at Columbia University working on the Riemann Hypothesis.
(quoted from In the Shadow of Gotham)
Gifted in math, Sarah had just begun her fourth year in Columbia's graduate program in mathematics, having finished her undergraduate degree at Barnard. She was apparently doing well in her work, and had even published tow papers  the primary criterion for succeeding in academic work. According to Abigail, Sarah had seemed content and happy and while certainly she had experienced the usual difficulties on would expect a woman to encounter in graduate education  especially in a man's field such as mathematics  Sarah had never complained.

(quoted from In the Shadow of Gotham)
There was a modern Hammond typewriter at the desk, next to which was a notebook. On its cover, Sarah Wingate had written her name, as well as a title  THE RIEMANN HYPOTHESIS. Inside, line after line was filled with mathematical symbols and equations that resembled mere gibberish.

This book was strangely reminiscent of No One You Know, also about a murdered sister whose notebooks reveal that she was working on the Riemann Hypothesis. However, this book is more of a standard murder mystery where the primary focus is on capturing the killer.
Contributed by
Jeanne Clelland
The novel is set in New York in the early 20th century, where the murder victim is a female graduate student in mathematics at Columbia. Her work in mathematics is described briefly as part of the murder investigation.
Mathematics or no, the book was an enjoyable read. I guessed who the murderer was fairly early on, but not his/her motive, so there were still enjoyable twists at the end. (The next novel in the series, "A Curtain Falls," involves no mathematics but is also an entertaining mystery novel.)

