In this paper, we propose a new kind of nonprioritized operator which we call two level credibility-limited revision. When revising through a two level credibility-limited revision there are two levels of credibility and one of incredibility. When revising by a sentence at the highest level of credibility, the operator behaves as a standard revision, if the sentence is at the second level of credibility, then the outcome of the revision process coincides with a standard contraction by the negation of that sentence. If the sentence is not credible, then the original belief set remains unchanged. In this article, we axiomatically characterize several classes of two level credibility-limited revision operators.

在本文中，我们提出了一种新的非优先算子，我们称之为两级可信度有限修正。当通过两级可信度限制修订进行修订时，有两个可信度级别和一个不可信度级别。当通过最高可信度的句子进行修改时，操作员的行为相当于标准修改，如果句子处于第二可信度，则修改过程的结果与该句子的否定标准收缩一致。如果句子不可信，则原始信念集保持不变。在本文中，我们公理化地描述了几类两级可信度有限的修正算子。