Refactoring is modifying a program without changing its external behavior. In this paper, we make the concept of external behavior precise for a simple answer set programming language. Then we describe a proof assistant for the task of verifying that refactoring a program in that language is performed correctly.

中文翻译：

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逻辑程序的外部行为和重构验证

重构是修改程序而不改变其外部行为。在本文中，我们将外部行为的概念精确化为简单的答案集编程语言。然后，我们描述一个证明助手，用于验证用该语言重构程序是否正确执行。