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Guo-Jie Li

Publications and source records attributed to Guo-Jie Li.

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$\ell$-Log-momotonic and Laguerre Inequality of P-recursive Sequences

We consider $\ell$-log-momotonic sequences and Laguerre inequality of order two for sequences $\{a_n\}_{n \ge 0}$ such that \[ \frac{a_{n-1}a_{n+1}}{a_n^2} = 1 + \sum_{i=1}^m \frac{r_i(\log n)}{n^{α_i}} + o\left( \frac{1}{n^β} \right), \] where $m$ is a nonnegative integer, $α_i$ are real numbers, $r_i(x)$ are rational functions of $x$ and \[ 0 < α_1 < α_2 < \cdots < α_m < β. \] We will give a sufficient condition on $\ell$-log-momotonic sequences and Laguerre inequality of order two for $n$ sufficiently large. Many P-recursive sequences fall in this frame. At last, we will give a method to find the $N$ such that for any $n\geq N$, log-momotonic inequality of order three and Laguerre inequality of order two holds.

math.CO

Gosper Summability of Rational Multiples of Hypergeometric Terms

By telescoping method, Sun gave some hypergeometric series whose sums are related to $π$ recently. We investigate these series from the point of view of Gosper's algorithm. Given a hypergeometric term $t_k$, we consider the Gosper summability of $r(k)t_k$ for $r(k)$ being a rational function of $k$. We give an upper bound and a lower bound on the degree of the numerator of $r(k)$ such that $r(k)t_k$ is Gosper summable. We also show that the denominator of the $r(k)$ can read from the Gosper representation of $t_{k+1}/t_k$. Based on these results, we give a systematic method to construct series whose sums can be derived from the known ones. We also illustrated the corresponding super-congruences and the $q$-analogue of the approach.

math.NT