chapter  1
Relativistic invariance
Pages 6

The classical physics description of all nature phenomena consists of two essentially different components-matter particles and fields. Movements of mass points, from which as it seemed at that time, one could build all the variety of objects existing in nature, were completely defined by laws of Newton mechanics. A classical particle is a small object localized in a restricted region of space. In the most general case, the position of the particle is defined by three spatial coordinates, that is, its maximum number of degrees of freedom equals three. Having set initial conditions and having solved the evolution equation (the second Newton law), we obtain exhaustive information about the particle.