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lutz2022complete (661B)


      1 # lutz2022complete
      2 
      3 [academic_paper] by [carsten] and [leif]
      4 
      5 Complexity [trichotomy] for [ontology_mediated_query] about [el] class:
      6 
      7 We know that every [OMQ] from (EL,AQ) (or (EL,CQ)) falls into one of the following classes:
      8 
      9 - [AC0] / [FO-rewritable]
     10 - [NL]
     11   - but there is actually an infinite hierarchy here: every [OMQ] that can be evaluated in NL translates into an equivalent [linear_datalog] program, and for every [datalog_width] k of such a program ([arity] of [IDB_relations]) we find an [OMQ] that actually needs width at least k in the rewriting (equivalently: has [pathwidth] k)
     12 - [PTime]
     13 
     14 [Open_question]: extend to [ELI]
     15 
     16 Up: [academic_paper]