Stability of void:triples across TPF requests

Hello all,

In context of reading on detecting dataset changes, I was wondering if we ever discussed the stability of count estimates across TPF requests? In other words, presuming caching has expired already, will a request to the same TPF today and tomorrow guarantee the same estimate if the data hasn't changed? I found no mention of this in the spec: http://www.hydra-cg.com/spec/latest/triple-pattern-fragments/#metadata. Some storage systems that rely on probabilistic data structures for this estimate (e.g., Bloom filter, Count-Min Sketch) could return a different number for each query.


Best,

Miel