Please find the talks before December 31, 2018 at Previsous Talks

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**Time**: Wensday, January 16, 2019 at 14:00 –15:00 p.m.**Room**: N205**Title**:Arithmetic and combinatorics around power series**Speaker**: Chunlin Wang ( Sichuan Normal University,China)**Abstract**: Power series is widely used in various branches of mathematics. In this talk, we focus on arithmetic and combinatorial properties on it. We are mainly interested in two topics. First we introduce two conjectures posed by van der Poortern and Christol on diagonal power series over a number field. Then we present some recent progress on the rational-transcendental dichotomy of power series with a restriction on coefficients. -
**Time**: Wensday, January 16, 2019 at 15:00 –16:00 p.m.**Room**: N205**Title**:On the automaticity of sequences defined by continued fractions**Speaker**:Yining Hu ( Huazhong University of Science and Technology)**Abstract**: We prove that the sequences defined by the Stieltjes continued fractions associated with the Thue-Morse sequence and the period-doubling sequence are 2-automatic modulo 4. -
**Time**: Thursday, February 21, 2019 at 15:00 –16:00 p.m.**Room**: N109**Title**:Algorithms for difference families in finite abelian groups**Speaker**:Ilias S. Kotsireas (Wilfrid Laurier University, Canada)**Abstract**: We generalize a number of tools and theorems to search for difference families in cyclic groups, to the more general setting of arbitrary finite abelian groups. In particular, these include the power spectral density (PSD) test and the method of compression. Some illustrative examples will be presented, using Maple's GroupTheory package. This is joint work with Dragomir Z. Djokovic (University of Waterloo) pre-publication available at: https://arxiv.org/abs/1801.07627.