A wide variety of mathematical expressions printed in scientific and technical reports can be recognized by analyzing the two-dimensional layout structure. In this paper, the position relation between adjacent characters is analyzed for the purpose of automatic discrimination between baseline, subscript, and superscript characters. This analyzing is one of the most important parts of structure analysis. The proposed method is very promising, as the results reached up to (99.76%) over a very large database by using distribution map. This distribution map is defined by two important features, i.e., relative size and relative position.