Glossary for the working group

There have been a lot of terms being used in the mailing list but no 
definition of these terms.  The working group should try to use terms in a 
consistent manner.

I have attached a short glossary of some terms that have been frequently used 
in the working group so far plus a several more that are needed to give these 
terms meaning.   I also had to disambiguate several terms.  I also went ahead 
and added two terms that I think will start to show up quite soon (decoration 
and validation).

I tried to tie these terms back to ShEx, SPIN, and OWL constraints wherever 
possible and to give examples in several key cases.

Enjoy,

peter

Document:  A container for a sequence of Unicode characters available, which
may or not be the accessible via URL dereferencing.

RDF graph: See RDF 1.1 Concepts and Abstract Syntax.  RDF graphs may be
accessible via one or more URLs by dereferencing the URL and parsing
the resultant document.

Ontology: Something that provides information about classes and properties,
e.g, an RDF graph containing RDFS properties or a normal OWL ontology.  It
should be possible to transform the ontology into an RDF graph in a standard
way.  Ontologies may be accessible via one or more URLs, but it may require
more than URL dereferencing and parsing of the resultant document into an
ontology, for example importing may have to be performed.

Schema: Something that provides a set of constraints that can be applied to
a target, e.g., a SPIN document, a ShEx document, or an ontology.  It should
be possible to transform the schema into an RDF graph in a standard way.
Schemas may be accessible via one or more URLs, but it may require more than
URL dereferencing and parsing of the resultant document into a schema, for
example importing may have to be performed.

Constraint: A constraint is a component of a schema that says what needs to
be satisfied.  It may or may not include a scope (see below).

Skoped Constraint: A constraint that indicates where it is to be satisfied
on an RDF graph, e.g., a SPIN constraint (with both subject and object)
or an OWL axiom.
Example: Every person has at least one known name that is a string.

Unskoped Constraint/Shape: A constraint that cannot be validated against an
RDF graph without some extra information on where it is to be satisfied,
e.g., a labelled ShEx shape expression or SPIN ask or OWL description.
Example: Named things are those things that have at least one name and all
    their names are strings
Example: Things with at least one name that is a string

Constraint Condition/ShEx Rule: A component of a constraint
that carries a condition that needs to be evaluated as part of validation,
e.g., a ShEx rule, or an OWL description, or clause in a SPIN SPARQL query.
Example: At least one name and all names are strings
Example: At least one name that is a string

Recognition Constraint: A constraint that introduces vocabulary, e.g., a
labeled ShEx expression or an OWL axiom defining a new class.
Example: Named things are those things that have at least one name and all
    their names are strings
Example: Named people are those people that have at least one known name
  that is a string.

Recursive Recognition Constraints: A recognition constraint that refers to
itself, either directly or indirectly.
Example: Nicely named things are those things that have at least one name
  and all their parts are nicely named things
Example: Unnicely named things are those things that have at least one name
  and some of their parts are not unnicely named things

Decoration: Additional information associated with a constraint, e.g, SPIN
CONSTRUCT constructs or annotations on OWL axioms.  This information may for
example provide severity or other information about constraint violations.
Example: This is the person name constraint
Example: Violations produce warning for person name constraint violation
Example: Return violating object and any of its names that are not strings

Validation: The process of taking a schema and an RDF graph and maybe some
other information, such as an ontology or some skoping information, and at
least determining whether the RDF graph satisfies (does not violate) the
schema.  Validation may produce more than just a boolean result if the
constraints of the schema have decorations.