Abstract
We prove that Sp(2k + l) admits at least two non-naturally reductive Einstein metrics which are Ad(Sp(k) × Sp(k) × Sp(l))-invariant if k < l. It implies that every compact simple Lie group Sp(n) for n ⩾ 4 admits at least 2[(n–1)/3] non-naturally reductive left-invariant Einstein metrics.
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Acknowledgements
This work was supported in part by the National Natural Science Foundation of China (Nos. 11571182, 11901300, 11931009), the Natural Science Foundation of Tian** (No. 19JCYBJC30600), and the Natural Science Research of Jiangsu Education Institutions of China (No. 19KJB110015).
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Chen, Z., Chen, H. Non-naturally reductive Einstein metrics on Sp(n). Front. Math. China 15, 47–55 (2020). https://doi.org/10.1007/s11464-020-0818-0
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DOI: https://doi.org/10.1007/s11464-020-0818-0