One Index for Subsumption and Roll-up across Time, Geography, and Ontology (opens in new tab)

Time-series, geospatial, and ontology systems each maintain a hierarchy -- day <= month <= year, zip <= city, is-a / part-of -- and each indexes it in a separate silo. We observe these are all subsumption posets, with one recurring workload: order testing (is x under y?) and hierarchical roll-up (aggregate a measure over everything under y). We present OEH, a single declarable index that, by a cheap structural probe, encodes a hierarchy as a nes...