The reliability validation of attribution fragments obtained with the fragment-based method. A) The vertical axis "Difference" denotes the probability difference of positive match and negative match, and the scope is from -1 to 1. The higher value means the fragment has a higher proportion of occurrence in positive molecules than negative molecules, which indicates that the fragment has more vital relevance to the specific property. B) The calculation process of difference value. The red highlights denote that the attribution fragments occur in the tested samples. C) Mechanism description of attribution fragments. The left column denotes the "Ground Truth" fragments with red highlights, and References [21, 22\cite{bib31,bib32}] give the related literature. The right column displays several obtained attribution fragments with red highlights. The "Top-k" denotes that the fragment ranks the k-th highest in the overall results for the molecule.