Published online by Cambridge University Press: 13 January 2016
Many results are known about test ideals and $F$-singularities for $\mathbb{Q}$-Gorenstein rings. In this paper, we generalize many of these results to the case when the symbolic Rees algebra ${\mathcal{O}}_{X}\oplus {\mathcal{O}}_{X}(-K_{X})\oplus {\mathcal{O}}_{X}(-2K_{X})\oplus \cdots \,$ is finitely generated (or more generally, in the log setting for $-K_{X}-\unicode[STIX]{x1D6E5}$). In particular, we show that the $F$-jumping numbers of $\unicode[STIX]{x1D70F}(X,\mathfrak{a}^{t})$ are discrete and rational. We show that test ideals $\unicode[STIX]{x1D70F}(X)$ can be described by alterations as in Blickle–Schwede–Tucker (and hence show that splinters are strongly $F$-regular in this setting – recovering a result of Singh). We demonstrate that multiplier ideals reduce to test ideals under reduction modulo $p$ when the symbolic Rees algebra is finitely generated. We prove that Hartshorne–Speiser–Lyubeznik–Gabber-type stabilization still holds. We also show that test ideals satisfy global generation properties in this setting.
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