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
Unified Task Force on 4 May 1993. Unified Task Force The Unified Task Force (UNITAF) was a US-led, United Nations-sanctioned multinational force, which operated in Somalia between . A United States initiative (code-named Operation Restore Hope), UNITAF was charged with carrying out United Nations Security Council Resolution 794 to create a protected environment for conducting humanitarian operations in the southern half of the country. After the killing of several Pakistani peacekeepers, the Security Council changed UNITAF's mandate issuing the Resolution 837 that establishes that UNITAF troops could use "all necessary measures" to guarantee the delivery of humanitarian aid in accordance to Chapter VII