Chaff

Any statement mentioning anything in this class is considered boring and purged by the cwm --purge option. This is a convenience, and does not have any value when published as a general fact on the web.

• Class

conclusion

All possible conclusions which can be drawn from a formula. The object of this function, a formula, is the set of conclusions which can be drawn from the subject formula, by successively applying any rules it contains to the data it contains. This is equivalent to cwm's "--think" command line function. It does use built-ins, so it may for example indirectly invoke other documents, validate signatures, etc.

• Property

conjunction

"A function to merge formulae: logical AND. The subject is a list of formulae. The object, which can be generated, is a formula containing a copy of each of the formulae in the list on the left. A cwm built-in function.

• Property

content

This connects a document and a string that represents it. (Cwm knows how to go get a document in order to evaluate this.) Note that the content-type of the information is not given and so must be known or guessed.

• Property

definitive document

When document D is the definitiveDocument for property P, any statement X P Y is true iff and only if the semantics of document D include that statement. For example, there may be a definitive document for the zipcode of airports by airport code, and so on. This is useful to let a reasoner know that it can extend its query to the given document. (Cwm will do this if its mode includes "r").

• Property

definitive service

When service S is the definitiveService for property P, any statement X P Y is true iff and only if a query to S returns that it is. The protocol for the service S depends on the scheme. For mysql protocol, the URI of the service is like sql://user:password@host.domain/database/. For example, there may be a definitive service for the zipcode of airports by airport code, and so on. This is useful to let a reasoner know that it can help resolve a query by delegating it to the service in question. (Cwm will do this if its mode includes "r").

• Property

dtlit

Takes a list of a string and a URI and creates a datatyped literal. For example, { ("2005-03-30T11:00:00" :tz) log:dtlit ?X } => { ?X a :Answer } . will produce "2005-03-30T11:00:00"^^:tz a :Answer .

• Property

equalTo

True if the subject and object are the same RDF node (symbol or literal). Do not confuse with owl:sameAs. A cwm built-in logical operator, RDF graph level.

• Property

Formula

• Class

implies

Logical implication. This is the relation between the antecedent (subject) and conclusion (object) of a rule. The application of a rule to a knowledge-base is as follows. For every substitution which, applied to the antecedent, gives a formula which is a subset of the knowledge-base, then the result of applying that same substitution to the conclusion may be added to the knowledge-base. related: See log:conclusion. (See the CWM manual for command line options to determine how rules from different sources are applied to and the results added to various formula.)

• Property

includes

The subject formula includes the object formula. Formula A includes formula B if there exists some substitution which when applied to B creates a formula B' such that for every statement in B' is also in A, every variable universally (or existentially) quantified in B' is quantified in the same way in A. Variable substitution is applied recursively to nested compound terms such as formulae, lists and sets. (Understood natively by cwm when in in the antecedent of a rule. You can use this to peer inside nested formulae.)

• Property

List

• Class

n3 string

The subject formula, expressed as N3, gives this string.

• Property

N3Document

A document which, which parsed as Notation3 as defined in general by http://www.w3.org/DesignIssues/Notation3.html and this schema, conveys the intent of the author by the semantics defined on those specifications, and the semantics defined by the specifications of any other identifiers used in the document.

• Class

notEqualTo

Equality in this sense is actually the same URI. A cwm built-in logical operator.

• Property

notIncludes

The object formula is NOT a subset of subject. True iff log:includes is false. The converse of log:includes. (Understood natively by cwm. The subject formula may contain variables. (In cwm, variables must of course end up getting bound before the log:include test can be done, or an infinite result set would result) Related: See includes

• Property

Other

• Class

output string

The subject is a key and the object is a string, where the strings are to be output in the order of the keys. See cwm --strings in cwm --help.

• Property

parses to

The subject string, parsed as N3, gives this formula.

• Property

racine

For anything identified by a URI with a fragid, this is the thing identified by the same URI without a hash or fragid. For anything else, it is itself.

• Property

rawType

This is a low-level language type, one of log:Formula, log:Literal, log:List, log:Set or log:Other. Example: log:semanticsOrError returns either a formula or a string, and you can check which using log:rawType.

• Property

rawUri

This allows one to look at the actual string of the URI which identifies this, for anything, even a blank node or a formula. This peeks into the internal workings of cwm, and so is not normally used. Use log:uri instead.

• Property

semantics

The log:semantics of a document is the formula. achieved by parsing representation of the document. For a document in Notation3, log:semantics is the log:parsedAsN3 of the log:contents of the document. For a document in RDF/XML, it is parsed according to the RDF/XML specification to yield an RDF formula (a subclass of N3 log:Formula). [Aside: Philosophers will be distracted here into worrying about the meaning of meaning. At least we didn't call this function "meaning"! In as much as N3 is used as an interlingua for interoperability for different systems, this for an N3 based system is the meaning expressed by a document.] (Cwm knows how to go get a document and parse N3 and RDF/XML it in order to evaluate this. Other languages for web documents may be defined whose N3 semantics are therefore also calculable, and so they could be added in due course. See for example GRDDL, RDFa, etc)

• Property

semantics or error message

This connects a document and either the formula it parses to, or an error message explaining what went wrong with trying. See log:semantics. (Cwm knows how to go get a document and parse it in order to evaluate this.)

• Property

String

• Class

Truth

Something which is true: believe it as you would believe this. Understood natively by cwm in that it will execute rules in a formula declared a Truth within a formula it is already taking rules from.

• Class

uri

This allows one to look at the actual string of the URI which identifies this. (Cwm can get the URI of a resource or get the resource from the URI.) This is a level breaker, breaking the rule of not looking inside a URI. Use (eg with string:match) to replace RDF's old "aboutEach" functionality. Use to implement the URI spec and protocol specs, etc.

• Property