Role of exterior and evolutionary skew-symmetric differential forms in   mathematical physics
  A role of skew-symmetric differential forms in mathematical physics relates to the fact that they reflect the properties of conservation laws. The closed exterior forms correspond to the conservation laws for physical fields, whereas the evolutionary forms correspond to the conservation laws for material media.   Skew-symmetric differential forms can describe a conjugacy of any objects (that correspond to the conservation laws). The closed exterior forms describe conjugated objects. And the evolutionary forms, whose basis are deforming manifolds, describe the process of conjugating objects and obtaining conjugated objects. From the evolutionary forms the closed exterior forms are obtained.   This shows that material media generate physical fields. The relation between evolutionary and closed exterior forms discloses the relation between the equations of mathematical physics and field theories. This explains the field theory postulates.   Conjugacy is possible if there is symmetry. Symmetries of closed exterior forms, which are conditions of fulfilment of the conservation laws for physical fields, are interior symmetries of field theories. And symmetries of dual forms (due to the degrees of freedom of material media) are external symmetries of the equations of field theories. This shows connection between internal and external symmetries of field theories. 
L.I. Petrova (Moscow State University, Russia)