How to deal with Grouping terms for matching approaches

[matentzn]

We typically want to represent the matching approaches themselves, i.e. the techniques used, rather than their groupins, such as:

• Entity Alignment Matching
• Ontology Matching
• Knowledge Graph Matching

because we do not want these to crop up as part of our justifications in SSSOM. However, there is a valid case to wanting these properly defined here. We could accept them as terms, and exclude them from the SSSOM mapping_justification?

See #8