The landscape of six-dimensional supergravities is dramatically constrained by the cancellation of gauge and gravitational anomalies, but the full extent of its implications has not been uncovered. We explore the cancellation of global anomalies of the Dai-Freed type in this setting with abelian and simply laced gauge groups, finding novel constraints. In particular, we exclude arbitrarily large abelian charges in an infinite family of theories for certain types of quadratic refinements, including a specific one defined in the literature. We also show that the Gepner orientifold with no tensor multiplets is anomaly-free for a different choice, as well as a number of heterotic models with and without spacetime supersymmetry in six dimensions. The latter analysis extends previous results in ten dimensions to some lower-dimensional settings in the heterotic landscape.

六维超重力的景观受到规范和重力异常取消的极大限制，但其影响的全部范围尚未被揭示。我们探索在这种情况下用阿贝尔和简单的规范组消除 Dai-Freed 类型的全局异常，发现新的约束。特别是，我们在某些类型的二次细化的无限理论族中排除任意大的阿贝尔电荷，包括文献中定义的特定二次细化。我们还表明，对于不同的选择，没有张量多重态的格普纳东方褶皱是无异常的，以及许多具有或不具有六维时空超对称性的杂种优势模型。后一种分析将先前十个维度的结果扩展到杂种优势景观中的一些较低维度的设置。