FROM SPACE TO TIME - FURTHER DEVELOPMENT OF TENSOR COVARIANT DIFFERENTIAL THEORY AND COVARIANCE CONCEPT^1)

This paper focuses on two types of symmetry breakages in tensor analysis. One is the symmetry breakage in the concept that there is covariant differential of tensor with respect to coordinate, but there is no one with respect to time. Another is the symmetry breakage in the theory that there is covariant differential theory of tensor in space field, but there is no one in time field. This paper tries to mend the symmetry breakages on the basis of recent years research progresses. Firstly the history of extending the covariance thought is reviewed. Then the process of abstracting the concept of covariant differential with respect to time is developed. Finally the procedure of constructing the covariant differential theory of tensor in time field is summarized. It ultimately reveals the symmetry between the covariant differential theory in time field and the covariant differential theory in space field.