Professor, Department of Mathematics
Ph.D., The Pennsylvania State University, 1981
M.A., University of Western Ontario, 1976
B.Sc., University of Western Ontario, 1975
Dr. Littlejohn joined the Baylor faculty as the Chair of the Mathematics Department in January, 2007. He stepped down as Chair in July, 2019. Prior to coming to Baylor he taught at Utah State University (1983-2006) and the University of Texas at San Antonio (1981-1983). He obtained his B.Sc. and M.S. degrees in mathematics from the University of Western Ontario before earning his Ph.D. at Penn State University. He has traveled extensively throughout the world and, in particular, frequently to work with colleagues in various places in the United Kingdom, Spain, and Korea. His hobbies include listening to music, playing squash, and watching/listening to baseball games played by his favorite team, the Detroit Tigers.
Academic Interests and Research:
Dr. Littlejohn's research areas include orthogonal polynomials, inequalities, spectral theory of differential operators and special functions. When not working on research problems, he loves to study mathematics in other subjects (especially number theory) and to read popular books on mathematics and on various mathematicians.
Recent Selected Publications:
Radial and logarithmic refinements of Hardy's inequality, (with F. Gesztesy, I. Michael and M. Pang), St. Petersburg Math. J., 30(2019), No. 3, 429-436
Trace formulas applied to the Riemann ζ-function, (with M. Ashbaugh, F. Gesztesy, L. Hermi, K. Kirsten and H. Tossounian), in Integrability, Supersymmetry and Coherent States. A Volume in Honour of Professor Véronique Hussin, Sengül Kuru, Javier Negro, Luis M. Nieto (eds), CRM Series in Mathematical Physics, Springer, 2019.
Differential operator for discrete Gegenbauer-Sobolev orthogonal polynomials: eigenvalues and asymptotics (with Juan F. Mañas--Mañas, Juan J. Moreno--Balcázar and R. Wellman), J. Approx. Theory, 230 (2018) 32-49.
On Birman's sequence of Hardy-Rellich-type inequalities, (with F. Gesztesy, I. Michael and R. Wellman), J. Differential Equations 264 (2018), 2761-2801.
Factorizations and Hardy-Rellich-type Inequalities, (with F. Gesztesy), In Non-Linear Partial Differential Equations, Mathematical Physics, and Stochastic Analyis. The Helge Holden Anniversary Volume, F. Gesztesy, H. Hanche-Olsen, E. R. Jakobsen, Yu. Lyubarskii, N. H. Risebro, and K. Seip (eds), EMS Congress Reports, ETH-Zürich, 2018, pp. 207-226.
Self-adjoint operators in extended Hilbert spaces H⊕W: an application of the general GKN-EM theorem", (with R. Wellman), to appear in Operators and Matrices.Former Ph.D. Students:
Some Courses Taught at Baylor: