In
general relativity, the **relativistic disk** expression refers to a class of *
axi-symmetric* self-consistent solutions to
Einstein's field equations corresponding to the
gravitational field generated by
axi-symmetric isolated sources. To find such solutions, one has to pose correctly and solve together the ‘outer’ problem, a
boundary value problem for vacuum
Einstein's field equations whose solution determines the external field, and the ‘inner’ problem, whose solution determines the structure and the dynamics of the matter source in its own
gravitational field. Physically reasonable solutions must satisfy some additional conditions such as finiteness and positiveness of mass, physically reasonable kind of matter and finite geometrical size.^{
[1]}^{
[2]} Exact solutions describing relativistic static thin disks as their sources were first studied by Bonnor and Sackfield and Morgan and Morgan. Subsequently, several classes of exact solutions corresponding to static and stationary thin disks have been obtained by different authors.

**^**Guillermo A. González and Antonio C. Gutiérrez-Piñeres. (2012). "Stationary axially symmetric relativistic thin discs with nonzero radial pressure".*Classical and Quantum Gravity*.**29**(13): 13500. Bibcode: 2012CQGra..29m5001G. doi: 10.1088/0264-9381/29/13/135001. S2CID 119336024.**^**Antonio C. Gutiérrez-Piñeres, Guillermo A. González and Hernando Quevedo (2013). "Conformastatic disk-haloes in Einstein-Maxwell gravity".*Phys. Rev. D*.**87**(4): 044010. arXiv: 1211.4941. Bibcode: 2013PhRvD..87d4010G. doi: 10.1103/PhysRevD.87.044010. S2CID 119323477.