Anti-de Sitter space bell. It might be described as being the "opposite" of the surface of a sphere, which has a positive curvature. General relativity is a theory of the nature of time, space and gravity in which gravity is a curvature of space and time that results from the presence of matter or energy. Energy and mass are equivalent (as expressed in the equation "E" = "mc"), and space and time can be translated into equivalent units based on the speed of light ("c" in the "E" = "mc" equation). A common analogy involves the way that a dip in a flat
Lewin's equation influence present events. Past events can only have a position in the historical causal chains whose interweavings create the present situation."Lewin referred to this concept as the principle of contemporaneity. Lewin's equation Lewin's equation, "B" = "f"("P", "E"), is a heuristic formula proposed by psychologist Kurt Lewin as an explanation of what determines behavior. The formula states that behavior is a function of the person and his or her environment: formula_1 Where formula_2 is behavior, formula_3 is Person, and formula_4 is the environment. This equation was first presented in Lewin's book, "Principles of Topological Psychology", published in 1936. The equation