We prove that any two embeddings P^d ? Y ? X_1 , P^d ? Y ? X_2 , d ? 3, in two n-folds projective varieties X_1 , X_2 with normal bundle N_{Y |X_1} ? X_{Y |X_2} ? (n ? d)O_{P^d} (1) are formally equivalent. Moreover, we see that Y is G2 in both X_1 and X_2. As an immediate consequence of this result and if furthermore Y is G3 in both X_1 and X_2 then we deduce that the two embeddings are Zariski equivalent.

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Positive embeddings,Formal equivalence,Unirational varieties