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arXiv · hep-th/9512191

Anomalies, D-flatness and Small Instantons

R. G. Leigh
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Abstract

Recently, Witten has proposed a mechanism for symmetry enhancement in $SO(32)$ heterotic string theory, where the singularity obtained by shrinking an instanton to zero size is resolved by the appearance of an $Sp(1)$ gauge symmetry. In this short letter, we consider spacetime constraints from anomaly cancellation in six dimensions and D-flatness and demonstrate a subtlety which arises in the moduli space when many instantons are shrunk to zero size.

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R. G. Leigh. 1995-12-22. Anomalies, D-flatness and Small Instantons. https://doi.org/10.1016/0370-2693(96)00342-5

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