La relation différence et l'anti-isomorphie

This paper deals with pairs of binary relations defined on the same finite basis and which the 3-element restrictions are isomorphic and those of 5-element restrictions are isomorphic or anti-isomorphic. To each of these pairs, we associate an equivalence relation which yields a decomposition of these relations into classes that we will characterize. As application, we get the treshold of half-reconstruction for tournaments.