Daphne Der-Fen Liu

President's Distinguished Professor 2018
College of Natural & Social Sciences
Department of Mathematics
Office Location SHF205
323 343 2150


I was born in Taipei Taiwan, where I got my BS degree in Math. After spending two years at the Institute of Math, Academia Sinica in Taiwan as a research assistant, I came to the US for my Ph.D. at the University of South Carolina, Columbia under the supervision of Jerry Griggs.

Ever since joined the Cal State LA faculty in 1991, I have been pursuing both my teaching and research goals. I am extremely honored to be the recipient of the 2015 MAA (Mathematical Association of America) Southern California and Nevada Sectional Distinguished Teaching Award, as well as a recipient of the Cal State LA Outstanding Professor Award (2003), and Distinguished Women Award (2016) and President's Distinguished Professor Award (2018).


Teaching is a fulfilling and rewarding job! To see my student learn, get interested in the subject, and make achievements is the best rewards for a teacher.

During the past years, I have taught more than two dozen math courses ranging from collage algebra to graduate courses. Some years ago I created an upper division graph theory course, which is now offered annually. In addition, I have taught several graduate seminar courses on special topics, and mentored many student research projects for both undergraduate and graduate students.

I am also interested in incorporating effective teaching strategies into my classes to enhance student learning. Currently, I am working on a flipped classroom grant (jointly with faculty from several Cal State campuses) funded by the US Department of Education.


My research interests are in graph theory and combinatorics. I have been working on the following topics:

  1. Graph coloring parameters of distance graphs and relations to number theory problems: Relating chromatic number, fractional chromatic number, and circular chromatic number of distance graphs to the "density of integral sets with missing differences" and the parameter involved in the so called "lonely runner conjecture," and applying these connections to solving open problems in respective areas.
  2. Graph labelings motivated by the channel assignment problem: Radio labeling, backbone coloring, distance two labeling, circular distance two labeling, etc.
  3. Applying topology (Tucker Lemma, Ky Fan Lemma, Borsuk-Ulam Theorem etc) to study graph coloring problems.
  4. Graphs colorings: Vertex coloring, circular coloring, fractional coloring, list-coloring, strong edge-coloring, and on-line coloring of graphs.

Currently, my research is partially supported by the National Science Foundation (NSF) under a grant entitled "Graph Coloring and Choosability" (2016-2019), and I am a faulty mentor for the NASA CSULA Direct STEM grant (2015-2020).

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Ph.D. Math. 1991

  • University of South Carolina, Columbia.
  • Advisor: Jerrold R. Griggs. Dissertation Title: Graph Homomorphism and the Channel Assignment Problem.

B.S. Math. 1985

  • National Central University, Taiwan.