Hi, Sophie. At the risk of sounding defensive, let me observie that the view of a tagged hierarchical structure in the Three Panes view is not alogical, and has important consequences for guiding the user as to how to properly assign tags wihin a hierarchical tag structure. That, in turn, will be of fundamental importance in the operation of a future AI (Artificial Intelligence) feature to suggest potentially useful tags for a selected document, in much the same way that the Classify feature suggests potentially appropriate groups into which a document might be classified.
Lets create a little database using the tag structure and content of your example above, for a hierarchical PERSON tag.
In the Three Panes view of the Tags, if I click on the PERSON tag, no content is displayed. That’s correct, because no document was assigned to that tag. And that’s important, because a) there should be no content assigned to the top level of a hierarchical group and b) the future AI to suggest tag(s) for a document should never choose an empty tag group, but should examine only those tag groups that hold document replicants, and suggest one or more based on the contextual relationships of the contents of tag groups to the document being evaluated.
If I click on the WOMAN tag in Three Panes I see that one document has been assigned that tag. If I examine the Tags Bar I see two tags for that document, PERSON and WOMAN. That’s correct, as the document was assigned the WOMAN tag, which is a child of the PERSON tag.
Let’s click on the PERSON tag in the Tags Bar. It shows 1 document, the same one that was assigned the WOMAN tag. And that’s correct, as it is displaying the single document that has both tags. If I instead click on the MAN tag in Three Panes and select one of the documents so tagged, it will also display two tags in the Tags Bar, PERSON and MAN. Now if I click on the PERSON tag in the Tags Bar it will show two documents, the only two in the database that meet the two-tag criterion.
Now let’s switch to the Tags view, which displays a flat list of tags for the database. If I click on the PERSON tag (which shows the number meeting that tag is 3) I do indeed see three documents displayed, which is again correct. A total of three documents in the database inherited the PERSON tag.
Many users assign tags by dragging documents into the Tags structure in the Three Panes view. To repeat, documents should not be tagged at the top level of a hierarchy, as that’s ambiguous. If necessary, additional subgroup(s) in the hierarchy should be created, even if the subgroup is a miscellaneous one.
Let’s illustrate that by a hypothetical example. Not long ago a group petitioned the European Union court to declare (as I recall) a chimpanzee as a person. If the court had ruled favorably, we would have to modify our little database by adding two additional subgroups, HUMAN and CHIMPANZEE under PERSON, and subsuming the existing subgroups for MAN and WOMAN under the HUMAN group. If we then added MALE and FEMALE tags under CHIMPANZEE and populated them with some documents, the number of documents subsumed under the PERSON tag would change in Tags view, but the number of documents subsumed under the HUMAN tag would remain the same as the previous total for PERSON.
As Christian noted, the fact that Tags are displayed in Three Panes as they are currently doesn’t mean that the display may not change in the future. There will be continued evolution of Tags.
But I’ll argue that the present display of the Tags group in Three Panes has intuitive value, especially for hierarchical tags, and is supportive of the future AI feature to guide the user in appropriate assignments of tags to documents, which should NOT be assigned at the top level of a tag hierarchy, in this case, PEOPLE. (If so assigned, items should be reclassified into lower-level tags, else the organization becomes ambiguous and the future AI feature will be weakened.)
So I don’t think issues of set theory are applicable as suggesting that the content of the PERSON tag when clicked in the text pane should be non-null in the Three Panes view of Tags (or that the item counts are wrong), but of course they are applicable in the case of the Tags view of the PERSON tag as well as of the other tags under the PERSON hierarchy.
Do I make any sense?