| Заглавие | Two properties of the partial theta function |
| Вид публикация | Journal Article |
| Година на публикуване | 2025 |
| Автори | Kostov V |
| Списание | Annuaire de l’Université de Sofia “St. Kliment Ohridski”. Faculté de Mathématiques et Informatique |
| Том | 112 |
| Start Page | 77 |
| Pagination | 77-91 |
| ISSN | 1313-9215 (Print) 2603-5529 (Online) |
| ключови думи | limit density of the real zeros, partial theta function, separation in modulus |
| Резюме | For the partial theta function $\theta(q,z):=\sum_{j=0}^{\infty}q^{j(j+1)/2}z^j$, $q$, $z\in\mathbb{C}$, $|q|<1$, we prove that its zero locus is connected. This set is smooth at every point $(q^{\flat},z^{\flat})$ such that $z^{\flat}$ is a simple or double zero of $\theta(q^{\flat},.)$. For $q\in (0,1)$, $q\to 1^-$ and $a\geq e^{\pi}$, there are $o(1/(1-q))$ and $(\ln(a/e^{\pi}))/(1-q)+o(1/(1-q))$ real zeros of $\theta(q,.)$ in the intervals $[-e^{\pi},0)$ and $[-a,-e^{-\pi}]$ respectively (and none in $[0,\infty)$). For $q\in (-1,0)$, $q\to -1^+$ and $a\geq e^{\pi/2}$, there are $o(1/(1+q))$ real zeros of $\theta(q,.)$ in the interval $[-e^{\pi/2},e^{\pi/2}]$ and $(\ln(a/e^{\pi/2})/2)/(1+q)+o(1/(1+q))$ in each of the intervals $[-a,-e^{\pi/2}]$ and $[e^{\pi /2},a]$. |
| DOI | 10.60063/GSU.FMI.112.77-91 |
| Прикачен файл | Размер |
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