We produce a simple criterion and a constructive recipe to identify those self-adjoint extensions of a lower semi-bounded symmetric operator on Hilbert space which have the same lower bound as the Friedrichs extension. Applications of this abstract result to a few instructive examples are then discussed.

中文翻译：

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Friedrichs下界的自伴随扩展

我们产生一个简单的准则和一个构造性的公式来识别希尔伯特空间上一个下半界对称算子的那些自伴随扩展，这些自伴随扩展的下界与弗里德里希扩展的下界相同。然后讨论此抽象结果在一些说明性示例中的应用。