A regular expression is similar (and in fact suffices for this particular grammar production).

正则表达式与此相似(并且事实上它能够满足这种特定语法产品的需要)。

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This paper introduces a new tree algorithm that is for deleting superfluous symbol and production in grammar, and gives a practical example to check the algorithm.

介绍了文法化简中消除无用符号和无用产生式的树型算法，并通过实例予以验证。

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