We report on $25$ families of projective Calabi-Yau threefolds that do not have a point of maximal unipotent monodromy in their moduli space. The construction is based on an analysis of certain pencils of octic arrangements that were found by C. Meyer. There are seven cases where the Picard-Fuchs operator is of order two and $18$ cases where it is of order four. The birational nature of the Picard-Fuchs operator can be used effectively to distinguish between families whose members have the same Hodge numbers.

中文翻译：

---

octic 安排的 Picard–Fuchs 算子，I：孤儿案例

我们报告了 25 美元的投影 Calabi-Yau 三重家族，它们的模空间中没有最大单能单调点。该结构基于对 C. Meyer 发现的某些 octic 排列铅笔的分析。有七种情况，Picard-Fuchs 算子是二阶的，$18$ 是四阶的。Picard-Fuchs 算子的双有理性质可以有效地用于区分成员具有相同霍奇数的家庭。