We continue the study of the rational Picard group of the moduli space of Hitchin spectral covers started in Korotkin and Zograf (J Math Phys 59(9):091412, 2018). In the first part of the paper we expand the “boundary”, “Maxwell stratum” and “caustic” divisors introduced in Korotkin and Zograf (2018) via the set of standard generators of the rational Picard group. This generalizes the result of Korotkin and Zograf (2018), where the expansion of the full discriminant divisor (which is a linear combination of the classes mentioned above) was obtained. In the second part of the paper we derive a formula that relates two Hodge classes in the rational Picard group of the moduli space of Hitchin spectral covers.

中文翻译：

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Hitchin 覆盖空间上的判别类和 Hodge 类

我们继续研究从 Korotkin 和 Zograf 开始的 Hitchin 谱覆盖模空间的有理 Picard 群 (J Math Phys 59(9):091412, 2018)。在论文的第一部分，我们通过有理皮卡德群的标准生成器集扩展了 Korotkin 和 Zograf (2018) 中引入的“边界”、“麦克斯韦层”和“焦散”除数。这概括了 Korotkin 和 Zograf (2018) 的结果，其中获得了全判别因数（它是上述类的线性组合）的扩展。在论文的第二部分，我们导出了一个公式，该公式将 Hitchin 谱覆盖模空间的有理 Picard 群中的两个 Hodge 类联系起来。