摘要

We explore how the topology of spacetime fabric is encoded into the local structure of Riemannian metrics using the gauge theory formulation of Euclidean gravity. In part I, we provide a rigorous mathematical foundation to prove that a general Einstein manifold arises as the sum of SU(2)(L) Yang-Mills instantons and SU(2)(R) anti-instantons where SU(2)(L) and SU(2)(R) are normal subgroups of the four-dimensional Lorentz group Spin(4) = SU(2)(L) x SU(2)(R). Our proof relies only on the general properties in four dimensions: The Lorentz group Spin(4) is isomorphic to SU(2)(L) x SU(2)(R) and the six-dimensional vector space Lambda T-2*M of two-forms splits canonically into the sum of three-dimensional vector spaces of self-dual and anti-self-dual two-forms, i.e., Lambda T-2*M = Lambda(2)(+) circle plus Lambda(2)(-). Consolidating these two, it turns out that the splitting of Spin(4) is deeply correlated with the decomposition of two-forms on four-manifold which occupies a central position in the theory of four-manifolds.

  • 出版日期2011-12