On electrogravity duality

By resolving the gravitational field into electric and magnetic parts, we d efine an electro-gravity duality transformation and discover an interesting property of the field. Under the duality transformation, a vacuum/flat spa ce-time maps into the original space-time with a topological defect of glob al monopole/texture. The electrogravity-duality is thus a topological defec t generating process. It turns out that all black hole solutions possess du al solutions that imbibe a global monopole.