my notes from today's JC telecon 6/8/04

From: Benjamin Grosof (bgrosof@MIT.EDU)
Date: 06/08/04

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    Prof. Benjamin Grosof % notes from Joint Committee telecon 6/8/04
    % notes by Benjamin Grosof
    - Mike Dean
    - Deborah
    - Norman
    - Harold
    - Said
    - Benjamin
    - Sandro
    - Pat
    o news of SWSL [Benj]
    - upcoming F2F there for about July 16, plan to use RuleML nonmon LP and FOL
    - would be nice by then for us to have spec on FOL and of updated RuleML
    o news of WWW Conf. [Mike, Benj, Harold]
    - DevDay Rules on Web track was a highlight
    - relevant themes:  use of rules for services, combo of rules with ontologies
    o main agenda:  discussion of FOL strawmen from Benj and Said and from Pat
    Benj and Said presented theirs
    Benj: started top down, half-way worked out now
    aimed to support XML serialization
    done in style similar to previous RuleML abstract syntax
    Benj A to Mike/Pat Q: intended to be just straightforward classical FOL
    Benj: issue:  how to treat closed-ness?
    - tried to do that; Benj:  think strawman needs fixing actually in this regard
    Pat:  top-level in SCL every name not quantified over is treated as a constant
    issue:  do we want free variables?
    - query lang could be something separate, and query variables could
    be viewed as existentially quantified at outer scope
    Benj: issue: how do we represent in the grammar the sufficiency of binding?
    I.e., so that XML parser etc. tools can do it?
    Seems we have to specify it as a separate constraint for implementers
    - general discussion about this, seemed to agree there's no other way.
    Pat:  if you can recognize variables as a separate syntactic category
    Benj:  I propose:
    - have syntactically explicit variables, as in current RuleML and SWRL
    - have perhaps an ability to declare in a collection of
    FOL statements a convention for implicit
    universal (or perhaps also optionally existential) quantification at
    outermost scope -- or perhaps also optionally no quantification, i.e.,
    treatment as free variables
    Q by Mike:  relationship to RuleML?
    A by Harold:  we could introduce explicit quantifiers and also disjunction
    into RuleML.
    A by Benj:  yes, and more cf. Lloyd-Topor.
    For both the reducible-to-LP-expressiveness base (with mon, nonmon subcases)
    and the general-FOL cases.
    Actually, that's been our plan in RuleML all along.
    Pat:  want to label an expression as fitting into / naming various
    expressive/syntactic classes, i.e., tag expressions with those names
    Benj:  yes. We should have an ontology of expressive/syntactic attributes
    and combinations, and be able to annotate/label with that at the grain of whole
    KB/rulebase or at the grain of individual rule/axiom/clause/expression.
    Pat and Benj:  The tagging should be open ended, including so that can help
    implementers declare constraints that facilitate processing.
    - Pat:  Let others define the relevant expressive/syntactic subsets.
    Pat:  key people working on SCL spec actively now are
    myself, Tanel Tammet, and Chris Menzel.
    Pat:  John Sowa now has a nice controlled English that maps to FOL.
    Harold: issue:  making DL folks happy
    - Pat:  we can view DL as subset of FOL, so that hopefully will
    Pat:  a recent proposal in SCL is that one can specify a special constraint
    that keeps it to classical FOL, i.e., mark all predicates or functions
    as not part of the domain of quantification
    - Benj:  that's rather blow by blow, it would be nice also to specify that
    at the grain of the whole KB
    - Pat:  yes
    Harold:  what's the status of XML syntax for SCL?
    Pat:  there's been a lot of arguments about that.
    Murray Altheim (at Open Univ. in England, background in Topic Maps)
    won the argument since he knows the most about it.
    The XML will be designed to be extensible rather than beautiful.
    Benj and Harold:  let's have RuleML and SCL efforts
    join forces sooner rather than later
    - Pat:  yes, I'll plan to start with a strawman
    Benj Q:  in SCL: what's rationale for equation being top level?
    To treat
    Pat A:  there was a lot of philosophical baggage.
    A key issue was that equality symbol should not be treated as part of
    domain of quantification.
    So essentially equality is treated specially syntactically -- it's
    essentially a first order language with equality.
    It has a fixed meaning -- a=b means that a and b denote the same thing.
    Intended as common garden equality.
    It applies to relations too; there, sameness of extension doesn't imply
    (necessarily) equality.
    Benj:  wrt plan -- how to go forward?
    Would be nice to have a single strawman, using the above ideas.
    Pat:  would be nice to get comments on SCL
    Benj:  let's try to converge efforts, i.e., RuleML/SWRL inspired XML syntax
    for SCL.  It could turn into an alternative or even main XML syntax for SCL.
    Pat: sounds great!
    - there's a year-old design document on guidelines
    and concerns on XML syntax, from Murray/SCL folks,
    I'll send that out to the committee list
    Pat:  warning:  SCL spirit tends to shrug shoulders about ability to check
    on things like arity etc.
    - Benj:  we could start out with a somewhat more constrained version that
    facilitates implementation, e.g., for services
    - Pat:  yes
    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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