Classical unified field theories since antisymmetry seemed essential for electromagnetism, the symmetry requirement was relaxed for one or both fields. Einstein's proposed unified-field equations (fundamental laws of physics) were generally derived from a variational principle expressed in terms of the Riemann curvature tensor for the presumed space-time manifold. In field theories of this kind, particles appear as limited regions in space-time in which the field strength or the energy density are particularly high. Einstein and coworker Leopold Infeld managed to demonstrate that, in Einstein's final theory of the unified field, true singularities of the field did have trajectories resembling point particles. However, singularities are
CJK Unified Ideographs CJK Unified Ideographs The Chinese, Japanese and Korean (CJK) scripts share a common background, collectively known as CJK characters. In the process called Han unification, the common (shared) characters were identified and named CJK Unified Ideographs. As of Unicode 11.0, Unicode defines a total of 87,887 CJK Unified Ideographs. The terms "ideographs" or "ideograms" may be misleading, since the Chinese script is not strictly a pictographic or ideographic system. Historically, Vietnam used Chinese ideographs too, so sometimes the abbreviation "CJKV" is used. This system was replaced by the Latin-based Vietnamese alphabet in the 1920s. The basic block named "CJK Unified