The Wagner Triangle is named after its famous creator, Sarah Wagner. The phenomen occurs mainly whenever a semantic model is extended and not remodelled due to acute lazyness of the modelling person. Furthermore it occurs when a subform is talking about a specific use of a thing in a certain context, however connects the context to the thing itself. It is a special problem with semantic modelling in WissKI due to the disambiguation feature of WissKI that specifically clears which concept in a certain path through the ontology is the target of the path.
1.) Subform talking about a thing
Usecase 1.1: Iconography
You have a form for information gathering about objects. These objects have iconography on them, e.g. different animals. Furthermore you want to gather specific information about the mouse in the context of the object - e.g. the mouse is grey.
Now we want another mouse that might be black. Depending on the setting in your system two different things might occur. If you have no disambiguation setting on the iconography field you get another instance for the mouse and this one is black - which works perfectly (green arrows). If you have a disambiguation on the iconography field the existing mouse is referenced and black is added to the colours of the mouse resulting in both colours being attached to the same mouse.
Usecase 2.1: Person role
Another example is the role of a person in the creation of an object. If you have the Object, which is created by the person and the role is directly attached to the person, then it becomes a fixed parameter of the person. This means that the role field will result in a complete list of all roles in the different creation events that relate to the person.
2.) Acute lazyness
The second problem occurs whenever you expand an existing model. Typical example is adding a comment field to a field that references to something. E.g. an Object has a reference field to refer to other objects that are used for comparison. Typically these reference fields to have a disambiguation to get the link to the second object. If you add a comment field to the existing model and a group around both of them you end up with the disambiguation of the path being a part of the semantics of the group. This is another typical example of a wagner triangle.