<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>47</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Adila Krisnadhi</style></author><author><style face="normal" font="default" size="100%">Carsten Lutz</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Nachum Dershowitz</style></author><author><style face="normal" font="default" size="100%">Andrei Voronkov</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Data Complexity in the EL Family of Description Logics</style></title><secondary-title><style face="normal" font="default" size="100%">Logic for Programming, Artificial Intelligence, and Reasoning, 14th International Conference, LPAR 2007, Yerevan, Armenia, October 15-19, 2007, Proceedings</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">10/2007</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1007/978-3-540-75560-9_25</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Springer</style></publisher><volume><style face="normal" font="default" size="100%">4790</style></volume><pages><style face="normal" font="default" size="100%">333-347</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We study the data complexity of instance checking and conjunctive query answering in the EL family of description logics, with a particular emphasis on the boundary of tractability. We identify a large number of intractable extensions of EL, but also show that in ELIf , the extension of EL with inverse roles and global functionality, conjunctive query answering is tractable regarding data complexity. In contrast, already instance checking in EL extended with only inverse roles or global functionality is EXPTIME-complete regarding combined complexity</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>47</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Adila Krisnadhi</style></author><author><style face="normal" font="default" size="100%">Carsten Lutz</style></author></authors><secondary-authors><author><style face="normal" font="default" size="100%">Diego Calvanese</style></author><author><style face="normal" font="default" size="100%">Enrico Franconi</style></author><author><style face="normal" font="default" size="100%">Volker Haarslev</style></author><author><style face="normal" font="default" size="100%">Domenico Lembo</style></author><author><style face="normal" font="default" size="100%">Boris Motik</style></author><author><style face="normal" font="default" size="100%">Anni-Yasmin Turhan</style></author><author><style face="normal" font="default" size="100%">Sergio Tessaris</style></author></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Data Complexity in the EL family of DLs</style></title><secondary-title><style face="normal" font="default" size="100%">Proceedings of the 2007 International Workshop on Description Logics (DL2007), Brixen-Bressanone, near Bozen-Bolzano, Italy, 8-10 June, 2007</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">06/2007</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://ceur-ws.org/Vol-250/paper_15.pdf</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">CEUR-WS.org</style></publisher><volume><style face="normal" font="default" size="100%">250</style></volume><language><style face="normal" font="default" size="100%">eng</style></language></record></records></xml>