The doctoral dissertation in the field of Mathematics will be examined at the the Faculty of Science and Forestry online.
MSc Hui Yu’s dissertation focuses on value distribution of meromorphic functions and on linear differential and difference equations in a complex domain. The research is based on Nevanlinna theory and its three variants (shift difference, ?-difference and Askey-Wilson), and it improves and generalizes some previously known results.
Several new refined results concerning linear differential equations improve a celebrated Frei’s theorem in the sense of offering a larger number of infinite-order solutions in both complex plane and unit disc cases. Moreover, these results give the asymptotic lower bounds for the growth of solutions. Analogous results are also studied for shift difference and ?-difference equations.
The dissertation also contains several results on linear ?-difference and Askey-Wilson divided difference equations by means of a ?-order, which is a growth scale enabling a continuous transition between the classical order and the logarithmic order. Consequently, previously known results in terms of the classical order and the logarithmic order follow as special cases.
It is also proved that logarithmic Borel exceptional values cannot exist simultaneously for a transcendental meromorphic function with its shift difference or with its ?-difference.
The doctoral dissertation of Master of Science Hui Yu entitled Results on value distribution of meromorphic functions of slow to moderate growth, and on complex differential and difference equations will be examined at the Faculty of Science and Forestry on the 1st of October at 12 noon. The opponent will be Professor Kai Liu from the Nanchang University, and the custos will be Professor Risto Korhonen from the University of Eastern Finland. The public examination will be held in English and it can be followed online.
