Fan Chung
Fan-Rong King Chung Graham (; born October 9, 1949), known professionally as Fan Chung, is a Taiwanese-born American mathematician who works mainly in the areas of spectral graph theory, extremal graph theory and random graphs, in particular in generalizing the Erdős–Rényi model for graphs with general degree distribution (including power-law graphs in the study of large information networks). Biography. Since 1998, Chung has been the Paul Erdős Professor in Combinatorics at the University of California, San Diego (UCSD). She received her doctorate from the University of Pennsylvania in 1974, under the direction of Herbert Wilf . After working at Bell Laboratories and Bellcore for nineteen years, she joined the faculty of the University of Pennsylvania as the first female tenured professor in mathematics. She serves on the editorial boards of more than a dozen international journals. Since 2003 she has been the editor-in-chief of "Internet Mathematics". She has been invited to give lectures at many conferences, including the International Congress of Mathematicians in 1994 and a plenary lecture on the mathematics of PageRank at the 2008 Annual meeting of the American Mathematical Society. She was selected to be a Noether Lecturer in 2009. Chung  has two children; the first child was born during her graduate studies from her first marriage. She was married to the mathematician Ronald Graham from 1983 until his death in 2020. They were close friends of the mathematician Paul Erdős, and have both published papers with him – 13 in her case; thus, both have Erdős numbers of 1. She has published more than 200 research papers and three books: In 2012, she became a fellow of the American Mathematical Society. Biography. Fan Chung was born on October 9, 1949 in Kaohsiung, Taiwan. Under the influence of her father, an engineer , she became interested in mathematics, especially in the area of combinatorics in high school in Kaohsiung. After high school, Chung entered the National Taiwan University (NTU) to start her career in mathematics formally. While Chung was an undergraduate, she was surrounded by many female mathematicians, and this helped encourage her to pursue and study mathematics. After graduating from NTU with a B.S. in mathematics, Chung went on to the University of Pennsylvania to pursue a career in mathematics. There she obtained the highest score in the qualifying exam by a wide margin, catching the attention of Herbert Wilf, who would  eventually become her doctoral advisor. Wilf suggested Ramsey theory as a subject Chung could work on. During a single week studying material Chung had come up with new proofs for established results in the field. Wilf said: "My eyes were bulging. I was very excited. I asked her to go to the blackboard and show me. What she wrote was incredible! In just one week, from a cold start, she had a major result in Ramsey theory. I told her she had just done two-thirds of a doctoral dissertation." Chung was awarded a M.S. in 1972 and a Ph.D.  two years later. By this time, she was married and had already given birth to her first child. The same year she received her Ph.D. and started working for the Mathematical Foundations of Computing Department at Bell Laboratories in Murray Hill, New Jersey. The position at Bell Laboratories was an opportunity to work with other excellent mathematicians, but also it contributed to her mathematical world powerfully. She published many impressive mathematical papers and published many joint papers with Ron Graham. After twenty years of work at Bell Laboratories and Bellcore, Chung decided to go back to the University of Pennsylvania  to become a professor of mathematics. In 1998, she was named Distinguished Professor of Mathematics at the University of California, San Diego. To date, she has over 200 publications to her name. The two best known books are "Spectral Graph Theory" and "Erdős on Graphs". "Spectral Graph Theory" studies how the spectrum of the Laplacian of a graph is related to its combinatorial properties. "Erdős on Graphs", which was jointly written by Fan Chung and Ron Graham, studies many of Paul Erdős problems and conjectures in graph theory. Beyond her contributions to graph theory, Chung has used her knowledge to  connect different fields of science. As she wrote in "Graph Theory in the Information Age", Chung's life was profiled in the 2017 documentary film "Girls who fell in love with Math". Bell Laboratories. In 1974, Fan Chung graduated from the University of Pennsylvania and became a member of Technical Staff working for the Mathematical Foundations of Computing Department at Bell Laboratories in Murray Hill, New Jersey. She worked under Henry Pollak. During this time, Chung collaborated with many leading mathematicians who work for Bell Laboratories such as Ron Graham. In 1975, Chung published her first joint paper with Graham  on "Multicolor Ramsey Numbers for Complete Bipartite Graphs" which was published in the "Journal of Combinatorial Theory". In 1983 the Bell Telephone Company was split up. Since Pollak joined and became head of a research unit within a new company, he asked Chung to become Research Manager. Until 1990, she was one of the first to receive a fellowship to spend a sabbatical at a university. She supervised many mathematicians in the unit. According to Chung's words, although people respect her because of the power to make decisions with positions in management, she prefers to be respected because of  her achievement in mathematics. Since then, she has returned to the academic world. Ron Graham. Fan Chung's first marriage ended in divorce in 1982. However, when she worked at Bell Laboratories, she met Ronald Graham. During that time, they became close friends and published many joint papers in graph theory, eventually marrying in 1983. In Paul Hoffman's book "The Man Who Loved Only Numbers", regarding her marriage with Graham, Chung said: In 1998, Graham and Chung co-wrote the book "Erdős on Graphs." Research. Spectral graph theory. Among Fan Chung's publications, her contributions to spectral graph theory  are important to this area of graph theory. From the first publications about undirected graphs to recent publications about directed graphs, Fan Chung creates the solid base in the spectral graph theory to the future graph theorist. Spectral graph theory, as one of the most important theories in graph theory, combines the algebra and graph perfectly. Historically, algebraic methods treat many types of graphs efficiently. Her work initiated a geometric approach to spectral graph theory with connections to differential geometry. According to the biography "Fan Rong K Chung Graham", "Spectral graph theory studies how the spectrum of the Laplacian of  a graph is related to its combinatorial properties.". In 1997, the American Mathematical Society published Chung's book "Spectral graph theory". This book became a standard textbook at many universities and is the key to study Spectral graph theory for many mathematics students who are interested in this area. Fan Chung's study in the spectral graph theory brings this “algebraic connectivity” of graphs into a new and higher level. Network science. Fan Chung's work in random graph models shed new light on the field of network science. Many real-world large information networks (such as Internet Graphs, Call  Graphs, and Collaboration Graphs, etc.) have been observed to be well approximated by a power law distribution. Fan Chung's work in the Chung-Lu model, pioneered the theory of treating random graphs with arbitrary degree distributions, including the power law graphs. Her work provides a solid framework for quantitative and rigorous analysis for modeling and analyzing large complex networks. It also often serves as a popular benchmark for comparing new graph models in network science. In 2006, the American Mathematics Society and the Conference Board of the Mathematical Sciences co-published Fan Chung and Linyuan Lu's book "Complex  Graphs and Networks". The book gave a well-structured exposition for using combinatorial, probabilistic, spectral methods as well as other new and improved tools to analyze real-world large information networks. Quasi-random graphs. Fan Chung, together with Ronald Graham and Richard Wilson, introduced a strong notion of equivalence among graph properties through the control of error bounds and developed the theory of quasi-random graphs. In a series of research papers (with several coauthors), she showed that a large family of graph properties is equivalent in the sense that if a graph satisfies any one of the properties, it  must satisfy all of them. The set of equivalent quasi-random properties includes a surprisingly diverse collection of properties, and therefore provides efficient methods for validating graph properties. Many (but not all) random graph properties are quasi-random. The notion of quasi-randomness has been extended to many other combinatorial structures, such as sequences, tournaments, hypergraphs and graph limits. In general, the theory of quasi-randomness gives a rigorous approach to 'random-like' or 'pseudorandom' alternatives. Extremal graph theory. A basic question in extremal graph theory is to find unavoidable patterns and structures in graphs with given density or distribution . A complementary problem is to find a smallest graph which contains every member of a given family of graphs as subgraphs. In a series of work with Paul Erdős, Chung determined the sizes and structures of unavoidable graphs and hypergraphs. With several coauthors, she also derived many elegant and surprising results on universal graphs. Her fundamental contributions in these areas of extremal graph theory have many applications in parallel computations.