Figure 1. Similarity scores for a group of active compounds with each other and with negative examples based on MNA and QNA descriptors. 3CLpro, PLPro, RdRp, TMPRSS2 - abbreviations of the corresponding target proteins, "+" - an indication of a group of pairwise similarity estimates obtained between compounds active with respect to the target, "-" - an indication of a group of pairwise similarity estimates between compounds active with respect to the target targets and compounds for which this activity is absent or not studied (negative examples). The number of pairwise similarity scores is indicated in parentheses.