Unlike Jaccard, the corresponding difference function d = 1 − 2 | X ∩ Y | | X | + | Y | {\displaystyle d=1-{\frac {2|X\cap Y|}{|X|+|Y|}}} is not a proper distance metric as it does not possess the property of triangle inequality.
与Jaccard不同的是，相应的差异函数 d = 1 − 2 | X ∩ Y | | X | + | Y | {\displaystyle d=1-{\frac {2|X\cap Y|}{|X|+|Y|}}} 不是一个合适的距离度量措施，因为它没有三角形不等性的性质。