Equations of motion when masses move according to Newton's law of gravity. In general relativity, rotational motion is described by the relativistic angular momentum tensor, including the spin tensor, which enter the equations of motion under covariant derivatives with respect to proper time. The Mathisson–Papapetrou–Dixon equations describe the motion of spinning objects moving in a gravitational field. Unlike the equations of motion for describing particle mechanics, which are systems of coupled ordinary differential equations, the analogous equations governing the dynamics of waves and fields are always partial differential equations, since the waves or fields are functions of space and time. For a particular
Laws of technical systems evolution in TRIZ. The following authors, besides Altshuller, contributed most to it: Yuri Khotimlyansky (studied patterns of energy conductivity in technical systems), Vladimir Asinovsky (proposed principles of correspondence of various components of technical systems), Yevgeny Karasik (co-authored with Altshuller the law of transition from a macro-level to a micro-level, introduced the notion of dual technical systems and studied the patterns of their evolution). In his pioneering work of 1975, Altshuller subdivided all laws of technical systems evolution into 3 categories: Laws of technical systems evolution The laws of technical systems evolution are the most general evolution trends for technical systems discovered