High Quality Content by WIKIPEDIA articles! In differential geometry and theoretical physics, the classification of electromagnetic fields is a pointwise classification of bivectors at each point of a Lorentzian manifold. It is used in the study of solutions of Maxwell's equations and has applications in Einstein's theory of general relativity, but the theorem is a purely mathematical one. A (real) bivector field may be viewed, at any given event in a spacetime, as a skew-symmetric linear operator on a four-dimensional (real) vector space, ra Fabrb. Here, the vector space is the tangent space at the given event, and thus isomorphic as a (real) inner product space to E1,3. That is, it has the same notion of vector magnitude and angle (or inner product) as Minkowski spacetime.