Permutation-partition pairs were introduced by Stahl in 1980. These pairs are
generalizations of graphs and graphs on surfaces. They were used to solve some
problems for orientable embeddings of graphs. In this paper, we introduce a
particular type of permutation-partition pair, called permutation-bipartition
pair, which can be seen as generalizations of signed graphs and signed graph
embeddings. Some applications are given.Comment: 28 pages,12 figure