Abstract: When applying Dempster's rule of combination to fuse pieces of evidence, a combination paradox can occur. It is very difficult to acquire the law or relationship among these combination paradoxes with some different manifestations. In order to resolve this problem, the study is carried out by the aid of canonical decomposition which is used to transform the basic belief assignment into the combination of a set of generalized simple support function. Firstly, two typical counterexamples are analyzed, and then the common characteristic between them, neglecting belief, is summarized. On the basis of this, a further analysis is made. Two forms of neglecting belief and the rules of causing them are generalized. A further analysis of type Ⅱ neglecting belief is made. Some general conclusions,that type Ⅱ neglecting belief cannot occur,are presented. These generalized rules and conclusions provide not only the basis for applying Dempster's rule more reasonably to avoid combination paradoxes, but also the reference for modifying the combination method more effectively.

Key words: evidence theory, Dempster's rule of combination, combination paradox, canonical decomposition, neglecting belief