How to make sure that the thesaurus is valid?

PoolParty Thesaurus Server is fully compliant with most Semantic Web standards of the World Wide Web Consortium: RDF, SKOS and SPARQL. SKOS (Simple Knowledge Organization System) is a standard especially good for controlled vocabularies like taxonomies and thesauri. When importing a taxonomy, PoolParty will make validity checks for you. PoolParty's validity checker is also recommended by the W3C as a SKOS validator.

This validator which is a built-in feature of PoolParty also takes care while a thesaurus is edited that, for example, no circularities in your graph occur (a concept cannot be a broader and a narrower concept of another concept at the same time, also not if some concepts are in-between of a hierarchy). Additionaly, PoolParty Thesaurus Server provides means to make quality queries, which are not necessarily part of the SKOS ontology. Those quality checks are based on SPARQL, so you can extend them if you like to make additional quality checks of your thesaurus.