A correct Gellish English collection of expressions is presented in a Gellish Database table that satisfies at least the following rules:

Rule 1: Facts shall be expressed as binary relations between things

Facts shall be expressed in Gellish English by one or more binary relations, each of which shall relate two things on a single line in a Gellish Database table. A related thing may be anything, including an individual thing or a kind of thing, a single thing or a plural thing (collection) and may be real or imaginary. Only in the case of synonyms and translations the related things (referenced by their unique identifiers) shall be the same while their names may be different.

Rule 2: Each thing shall be defined by an explicit classification or specialization relation

This implies that each Gellish expression shall only only relate things (individual things and kinds of things or concepts) that are properly defined in one of the following three ways:
1. It is a concept that is already defined in the Gellish English Dictionary and is selected from that dictionary (its name or synonym and unique identifier).
2. It is a new concept (kind of thing) that is propertly defined occording to the Gellish [Proper definition of a concept|rules for proper definitions of concepts]]. This includes that the new concept is defined by the specification of an explicit specialisation relation that defines it as a (proprietary) subtype of one of the concepts that already exist in the Gellish English Dictionary. Definitions of new concepts can be issued as proposals for inclusion in the Open Source Gellish English dictionary.
For example: the definition of the concept oak tree as a subtype of tree is specified as follows:

• oak tree is a specialization of tree that differs from other kinds of trees by the aspect that ….

3. It is a new individual thing that is properly defined by means of at least one classification relation with one of the kinds of things that is selected from the Gellish Dictionary or by one of the new (proprietary) subtypes. For example, the introduction of John Doe as an individual person is specified as follows:

• John Doe is classified as a man (optionally described by some characteristics).

Rule 3: Each relation shall be classified by a standard relation type

Each relation shall be classified by a kind of relation (relation type) that is selected from the Gellish dictionary. Private extensions of the Gellish Dictionary with additional relation types are allowed, provided that is done
For example, for an electronic catalogue of fasteners it may be requirement that a bolt shall have a length. Such a fact shall be expressed by a relation that is classified by a standard relation type with unique identifier 4956 and shall have as 'name' the standard phrase 'shall have as aspect a'. So the Gellish English expression becomes:

Rule 4: The relation type shall be compatible with related objects

The relation type that classifies a relation determines the kinds of roles that shall be played by the related things. This implies that a related thing shall be suitable to play the kind of role that is required by the relation type. This is a semantics consistency rule.
Example 1: Assume that A is a performer of B. This implies that A shall be a physical object, because the ‘is a performer of’ relation type requires a first role (performer) that can only be played by a physical object. The second role (performed) is a role that can only be played by an occurrence. So B must be an occurrence.
Example 2: Assume that C is a specialization of D. This implies that C is a concept (kind of thing), because the ‘is a specialization of’ relation requires a first role that is a subtype, which can only be played by a concept (or a subtype of concept).
Further guidance and explanation about these requirements is provided in the document ‘Gellish English Dictionary Extension Manual’[1].

Software as well as Knowledge Models, Requirements Models, Product Models and Facility Information Models can be certified by the Gellish Forum as being Gellish compliant. For software this means that it is able to import and/or export data files that are Gellish compliant. Certified software can be recognized by the Gellish logo with the text ‘Gellish powered’ or one of its language specific variants, such as ‘Gellish English powered’. For models it means that they conform to the rules for being correct Gellish English or another Gellish variant. The above-mentioned rules are only those basic rules.

Continue with Data Modeling and Database Design in Gellish English

[1] See http://sourceforge.net/project/showfiles.php?group_id=28353.