Draft Proposed ISO Standard for Common Logic
A draft of the proposed Common Logic standard was presented at the
ISO SC32 meeting in Berlin in April:
http://philebus.tamu.edu/cl/docs/cl/32N1238-WD24707-CommonLogic.pdf
Harry Delugach, who is the official editor of the document, presented
the following slides about Common Logic at the Open Forum on Metadata,
which was collocated with the ISO meeting in Berlin:
http://philebus.tamu.edu/cl/docs/cl/Berlin_OpenForum_Delugach.pdf
One point that is not mentioned in WD 24707 or in Harry's slides is
that we have started to call the default notation used in the document
CLIF (Common Logic Interchange Format). CGIF (Conceptual Graph
Interchange Format) will be 100% compatible with CLIF, and the syntax
of CGIF and its mapping to and from CLIF will also be standardized
in the document. This document is still in development, and many of
the sections will be revised, often extensively, in the next few months.
The model theory and the first-order syntax are firm, but there may be
some extensions. A final (we hope) version will appear in April 2006,
and a close-to-final version should appear in 3Q05.
There is an old version of a draft CG standard on my web site, which
will be replaced by this new document. However, I intend to combine
much of the old material and quite a bit of new material in a tutorial
on CGs, which will discuss how to map all (or at least most) of the
current CG techniques to and from the standard.
The tutorial will add some features to CGIF that go beyond the standard,
such as actors. Whether or not those features get into the standard is
an issue that will be discussed on CG list. My intention is to define
actors formally as a notation for functional conceptual relations and
to include them in the standard with that definition. Any features
that go beyond purely functional forms (e.g., side effects) will not
be in the standard.
Following are a few excerpts from ISO WD 24707 on Common Logic.
John Sowa
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Introduction, page 7:
Common Logic is a logic framework intended for information exchange and
transmission. The framework allows for a variety of different syntactic
forms, called dialects, all expressible within a common XML-based
syntax and all sharing a single semantics.
Common Logic has some novel features, chief among them being a syntax
which is signature-free and permits 'higher-order' constructions such
as quantification over Common Logic classes or relations while
preserving a first-order model theory, and a semantics which allows
theories to describe intensional entities such as Common Logic classes
or properties. It also fixes the meanings of a few conventions in
widespread use, such as numerals to denote integers and quotation
marks to denote character strings, and has provision for the use
of datatypes and for naming, importing and transmitting content on
the World Wide Web using XML.
Scope, p. 9
This standard specifies a family of languages designed for use in the
representation and interchange of knowledge among disparate computer
systems.
The following features are essential to the design of this standard
• The language has declarative semantics. It is possible to
understand the meaning of expressions in the language without
appeal to an interpreter for manipulating those expressions.
• The language is logically comprehensive—at its most general,
it provides for the expression of arbitrary logical sentences.
The following are within the scope of this standard:
• interchange of knowledge among heterogeneous computer systems
• representation of knowledge in ontologies and knowledge bases;
• specification of expressions that are the input or output of
inference engines.
The following are outside the scope of this standard:
• the specification of proof theory or inference rules;
• specification of translators between the notations of heterogeneous
computer systems.
• free logics
• conditional logics
• methods of providing relationships between symbols in the logical
“universe” and individuals in the “real world”.
This document describes Common Logic’s syntax and semantics.
The standard defines an abstract syntax and an associated model-
theoretic semantics for a specific extension of first-order logic.
The intent is that the content of any system using first-order logic
can be represented in the standard. The purpose is to facilitate
interchange of first-order logic-based knowledge and information
between systems.
Issues relating to computability using the standard (including
efficiency, optimization, etc.) are not addressed.