Send the same enriched query (stemming, synonyms, etc) to both local index and Primo Central PC index ( important for blended search )
As default behavior, Primo not only looks for the patron's query, but according to the guessed language enriches the original keywords of the user with additional terms, in order to improve the performance. Linguistic features ( https://knowledge.exlibrisgroup.com/Primo/ProductDocumentation/TechnicalGuide/120Linguistic_Features ) may be customized by the systems librarian, for example removing or adding synonyms. But these changes affects only the results coming from the local index (i.e. the index built with records coming from the library's pipes for the catalogue, the institutional repository etc.). Primo Central (PC) records are not affected: for PC records the query enrichment is run separately and using the default synonyms, thus ignoring customization applied by the systems librarian.
Expecially in a blended search, results may therefore result hardly explainable or misleading.
To have a consistent behavior the enriched query used for local records should be the one used for PC records as well.
Luigi Siciliano commented
Two closely related ideas are:
new option/checkbox: "expand my results with synonyms"
Show the terms added to the patron's query by the linguistic features (i.e. stemming, synonyms etc.) http://ideas.exlibrisgroup.com/forums/308176-primo/suggestions/18551809-show-the-terms-added-to-the-patron-s-query-by-the
There is also a thread in the Primo ML having as subject:
[Primo] query enrichment is applied by default and is a bit a black box - need for improvements to linguistic features