Consider algos/softwares that take keywords in one document and match them (possibly a kind of set intersection) with keywords in N other documents, possibly producing a match ranking.
a. Is there a specific name for this?
b. Are there implementations in Java and PHP?
Example use cases would be
- patients submitting a list of symptoms and then software looking for matches against known conditions
- applicants submitting skillsets and looking for potential job matches
- dating websites