We study natural variations of the structure existing on the unit tangent sphere bundle of any oriented Riemannian 4-manifold . We find a circle of structures for which the induced metric is the usual one, the so-called Sasaki metric, and prove how the original structure has a preferred role in the theory. We deduce the equations of calibration and cocalibration, as well as those of pure type and nearly-parallel type.
Cite this article
Rui Albuquerque, Variations of gwistor space. Port. Math. 70 (2013), no. 2, pp. 145–160DOI 10.4171/PM/1929