notes from today's JC telecon 12/2/03

From: Benjamin Grosof (bgrosof@mit.edu)
Date: 12/02/03

  • Next message: Benjamin Grosof: "updated document with possible directions for SWRL"
    % notes from JC telecon 12/2/03
    % by Benjamin Grosof
    
    agenda:
    - (a bit) feedback on SWRL
    - (mainly) discussion of next steps and directions for SWRL;
    
    participants:
    Mike Dean
    Benjamin Grosof
    Harold Boley
    Ian Horrocks
    Peter Patel-Schneider
    Deborah McGuinness
    Sandro Hawke (joined late)
    (regrets from Said Tabet)
    
    
    %%%%
    
    more feedback on SWRL
    
    misc. questions raised in discussions:
    
    - what are semantics of Datalog
    
    - where to find the canonical definition of RuleML
    
    %%%%
    
    
    Mike and Benjamin briefly walked through possible directions
    from their emails
    
    Benj suggestions on next steps:
    
    overall, let's start with stuff that's relatively easy and uncontroversial
    as well as useful
    
    1. sensor built-ins starting with datatype comparisons and conversions
    
    2. n-ary predicates, which includes predicates not only
        being OWL classes and predicates
    - this is something the OWL and RDF efforts back-burnered
    - can do pretty straightforwardly via slots
    
    wrt n-ary:
    - Mike:  issue of supporting legacy n-ary stuff done in RDF
    - Benj:  how would they be any worse off than now, can always treat it as 2-ary
    
    Harold and Deborah and all:  let's be driven by use cases, incl. services
    
    possible work items for future:
    - look at use cases of doing n-ary, and of rules for services generally
    
    3. more Lloyd-Topor expressiveness, e.g.,
    - OR in the body -- is quite useful for practical purposes
    - this is pretty straightforward as syntactic sugar -- it's reducible to Horn
    - could also have existentials in the body -- particularly useful with n-ary
      . maybe wait on this til we have more use cases
    - could also have universals in the head
      . maybe wait on this til we have more use cases
    
    Peter:  worried that there be monsters here in this territory,
    since we're on top of / in combination with full DL not just within Horn,
    e.g., may break some implementations' behavior that wouldn't otherwise be
    broken;
    e.g., or if attempt later to give an autoepistemic logic kind of semantics
    (Benj:  often people talk about this in terms of intuitionistic rather
    than autoepistemic);
    e.g., if implement in the following fashion:
    query for the antecedent, then if that's satisfied,
    add the consequent with appropriate bindings
    -- since the DL sublanguage may contain [non-intuitionistic]
    disjunctive info
    
    Benj:  if we're using a FOL semantics then it's not problematic;
    your example reasoner is just of a
    (potentially) incomplete reasoner being (actually) incomplete
    
    %%%%
    
    for next week:
    
    Mike will present more about his suggestions on
    datatype comparisons/conversions builtins
    
    relevant paper to read for next week:
    paper by Ian Horrocks et al on datatype groups
    from ISWC-2003, is on Ian's webpage
    
    
    
    ________________________________________________________________________________________________
    Prof. Benjamin Grosof
    Web Technologies for E-Commerce, Business Policies, E-Contracting, Rules, 
    XML, Agents, Semantic Web Services
    MIT Sloan School of Management, Information Technology group
    http://ebusiness.mit.edu/bgrosof or http://www.mit.edu/~bgrosof
    
    



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