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

From: Benjamin Grosof (
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
    - (a bit) feedback on SWRL
    - (mainly) discussion of next steps and directions for SWRL;
    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
    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 or

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