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 field observed in Igor Stravinsky's Russian period, such as in "Les Noces", derived from his use of folk melodies as generating material and influenced by shorter pieces by Claude Debussy, such as "Voiles", and Modest Mussorgsky. In Béla Bartók's Bagatelles, and several of Alfredo Casella's "Nine Piano Pieces" such as No. 4 'In Modo Burlesco' the close intervallic relationship between motive and chord creates or justifies the great harmonic dissonance. Unified field In music, unified field is the 'unity of musical space' created by the free use of melodic material as harmonic material and vice versa. The technique is most associated