Comparison functions and choice correspondences

In this paper, we introduce the concept of a comparison function, which is a mapping g that assigns numbers to ordered pairs of alternatives (x, y) wi th the property that g(x, y)= -g(y,x). The paper discusses how some well-kn own choice correspondences on tournaments such as the uncovered set, the mi nimal covering set and the bipartisan set can be extended to this general f ramework. Axiomatic characterizations and properties are studied for these correspondences.