Abstract
We discuss the construction of Sp(2) Sp(1)-structures whose fundamental form is closed. In particular, we fund 10 new examples of 8-dimensional nilmanifolds that admit an invariant closed 4-form with stabiliser Sp(2) Sp(1). Our constructions entail the notion of SO(4)-structures on 7-manifolds. We present a thorough investigation of the intrinsic torsion of such structures, leading to the construction of explicit Lie group examples with invariant intrinsic torsion.
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This work was partially supported by FIRB 2012 “Geometria differenziale e teoria geometrica delle funzioni” and PRIN 2010-2011 “Varietà reali e complesse: geometria, topologia e analisi armonica”.
TBM thankfully acknowledges financial support from the Danish Council for Independent Research, Natural Sciences.
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CONTI, D., MADSEN, T.B. HARMONIC STRUCTURES AND INTRINSIC TORSION. Transformation Groups 20, 699–723 (2015). https://doi.org/10.1007/s00031-015-9325-x
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DOI: https://doi.org/10.1007/s00031-015-9325-x