Unstable Kodaira Fibrations
arXiv:math/0612571
Abstract
Being inspired by Ross' construction of unstable products of certain smooth curves, we show that the product of every smooth curve of genus at least 2 is not slope semistable with respect to certain polarisations. Besides, we produce examples of Kodaira-fibred surfaces of nonzero signature, which are not slope semistable with respect to some polarisations, and so they admit Kähler classes that do not contain any constant scalar curvature Kähler metrics.
12 pages