Abstract: This paper presented the defintions of positive similar transitive and negative similar transitive binary relation,considered the generalized rough sets based on these two kinds of binary relations, analyzed their properties,respectively, also gave the corresponding axiomatic characterizations. Finally, we investigated the correlations between these two kinds relations and other relations-based generalized rough sets. Some important conclusions were achieved.

Key words: Rough set, Equivalence relation, Similar transitive relation, Axiomatic characterizations