Two problems of theory of gravitation
This paper aims to discuss two issues that can have a significant impact on the foundations of the theory of gravitation: (1). The existence of relativity of space-time geometry with respect to the properties of used reference frame, which is a manifestation of the long-known fact of relativity of geometry of space and time with respect to properties of measuring instruments (Henri Poincare). (2). Lack of invariance of Einstein's equations with respect to the geodetic transformations preserving unchanged the equations of motion of test particles. Because of this, the physically equivalent states are described, generally speaking, by means of different solutions of these equations. In other words, there is no one-to-one correspondence between the solutions of these equations and the set of admissible physical states