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CALSCALE:GREGORIAN
METHOD:PUBLISH
UID:c0831784-08a1-43ab-885e-fe428dad9088
X-WR-CALNAME:[RATIO] Nina Pardal (U. Huddersfield\, UK)
X-WR-TIMEZONE:Europe/Paris
BEGIN:VTIMEZONE
TZID:Europe/Paris
TZUNTIL:20261025T010000Z
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TZNAME:CET
DTSTART:20241027T030000
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
RDATE:20251026T030000
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DTSTART:20240331T020000
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
RDATE:20250330T020000
RDATE:20260329T020000
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UID:c0831784-08a1-43ab-885e-fe428dad9088
DTSTAMP:20260425T192533Z
CLASS:PUBLIC
DESCRIPTION:Title: Rewriting consistent answers on annotated data\nAbstract
 : In this talk\, I'll be discussing results on consistent query answering 
 over databases annotated with values from naturally ordered positive semir
 ings. We define consistent answers as the minimum of the semiring values a
 chieved by evaluating the query over all database repairs. Focusing on sel
 f-join free conjunctive queries and key constraints\, we introduce a varia
 nt of first-order logic with limited negation and suitable semiring semant
 ics. The main result establishes that consistent answers are rewritable in
  this logic if and only if the query's attack graph is acyclic. This gener
 alizes a classical result for standard databases and provides a unified fr
 amework for various semirings\, including the bag\, tropical\, and fuzzy s
 emirings. Furthermore\, we show that self-join free conjunctive queries wi
 th cyclic attack graphs do not have a polynomial-time constant-approximati
 on algorithm under bag semantics\, unless P=NP.\n\n\nImport automatique de
 puis https://framagenda.org/remote.php/dav/public-calendars/D3yqF7nwys9amf
 yY?export par sync_icals_to_drupal.py pour M2F
DTSTART;TZID=Europe/Paris:20250306T133000
DTEND;TZID=Europe/Paris:20250306T143000
LOCATION:LaBRI 076
SEQUENCE:0
SUMMARY:[RATIO] Nina Pardal (U. Huddersfield\, UK)
TRANSP:OPAQUE
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