Human actions, the author observes create mutually diverging spacetimes. To provide a natural concept of event point—in the sense of Aldo Bressan—he proposes in part II [the author, same journal 73 (1982), no. 6, 221–225] to construct unique diffeomorphisms between certain pairs of diverging spacetimes. In the present paper, he (1) defines an equivalence relation, called "divergence'', for spacetimes and (2) presents some preliminary results (whose proofs will appear elsewhere) concerning spacetimes on which reference frames of a special sort exist. These frames play a fundamental role in the construction of the diffeomorphisms.
Diffeomorphisms constructively associated with mutually diverging spacetimes which allow a natural identification of event points in general relativity. I / Zampieri Gaetano. - In: ATTI DELLA ACCADEMIA NAZIONALE DEI LINCEI. RENDICONTI DELLA CLASSE DI SCIENZE FISICHE, MATEMATICHE E NATURALI. - ISSN 0392-7881. - STAMPA. - 73:5(1982), pp. 132-137.