P.R. Laws tit. 31, § 3343
Presumptions established by law may be destroyed by proof to the contrary, except in the cases in which it is expressly prohibited.
Only a judgment obtained in a suit for revision shall be effective against the presumption of the truth of the res adjudicata.
In order that the presumption of the res adjudicata may be valid in another suit, it is necessary that, between the case decided by the sentence and that in which the same is invoked, there be the most perfect identity between the things, causes, and persons of the litigants, and their capacity as such.
In questions relating to the civil status of persons, and in those regarding the validity or nullity of testamentary provisions, the presumption of the res adjudicata shall be valid against third persons, even if they should not have litigated.
It is understood that there is identity of persons whenever the litigants of the second suit are legal representatives of those who litigated in the preceding suit, or when they are jointly bound with them or by the relations established by the indivisibility of prestations among those having a right to demand them, or the obligation to satisfy the same.
History —Civil Code, 1930, § 1204.