Sangiorgi's normal form bisimilarity is call-by-name, identifies all the call-by-name meaningless terms, and rests on open terms in its definition. The literature contains a normal form bisimilarity for the call-by-value $\lambda$-calculus, Lassen's enf bisimilarity, which validates all of Moggi's monadic laws. The starting point of this work is the observation that enf bisimilarity is not the call-by-value equivalent of Sangiorgi's, because it does not identify the call-by-value meaningless terms. The issue has to do with open terms. We then develop a new call-by-value normal form bisimilarity, deemed net bisimilarity, by exploiting an existing formalism for dealing with open terms in call-by-value. It turns out that enf and net bisimilarities are incomparable, as net bisimilarity identifies meaningless terms but it does not validate Moggi's laws. Moreover, there is no easy way to merge them. To better understand the situation, we provide a detailed analysis of the rich range of possible call-by-value normal form bisimilarities, relating them to Ehrhard's call-by-value relational semantics.

翻译：桑吉奥尔吉的正常形式是双相似的, 以调用名称命名, 点出所有调用名的无意义术语, 并且以其定义中的开放术语为基础。 文献中包含调用名价$\ lambda$- calculus, Lassen 的普通形式是双相似的, 以确认Moggi的月经法。 这项工作的出发点是观察到, 双异性不是调用单价等同桑吉尔吉的法律, 因为它不识别调用单价的无意义术语。 问题与公开术语有关。 然后我们开发一种新的调用单价美元( lambda$- calcalulturus) 普通调用单价( $\ lambda$- calcalculus) 的固定格式, 利用现有的形式来处理调用名价法的开放术语。 由此可以看出, 电子和纯两异性( ) 的相对性并不相容, 因为纯两异性识别无意义的术语, 但它不确认莫吉的法律。 此外,, 很难将它们合并起来。 此外,, 也没有容易的方法。 为了更好地了解情况, 我们提供了一种特殊的双价的正常的双价关系。</s>