Аннотация:It is shown that there is a correspondence between field theory equations such as the Dirac, Shr\H{o}dinger, Maxwell, Einstein equations and closed exterior forms of a certain degree. Such a correspondence between the field theory equations and closed exterior forms of a certain degree reveals the internal connection between the field theory equations. At the same time, it was shown that closed exterior forms are associated with the equations of mathematical physics for material media, such as thermodynamic, gas-dynamic, electromagnetic, cosmological equations, etc. This indicates the connection between the field theory equations and the mathematical physics equations and reveals the foundations of field theory.