SBVR11 — SBVR Issue: What is a fact type form

Title: What is a fact type form?
Specification: SBVR
Version: 1.0
Source: Ed Barkmeyer, NIST, edbark@nist.gov

Summary:

In SBVR, clause 8.3.4, 'fact type form' has the definition:
"representation of a fact type by a pattern or template of expressions based on the fact type".

According to clause 8.3(.0), 'representation' is "actuality that a given expression represents a given meaning". Is "a pattern or template of expressions" an "expression"? According to 8.2, a 'signifier' is "expression that is a linguistic unit or pattern [of sounds or symbols]". So apparently there are expressions that are patterns and they can be signifiers.

Per 8.3.1, designation is the "representation of a concept by a sign", and a fact type is a concept, so it may have a representation that is a designation. But the UML diagram shows that a fact type form is not a designation. So presumably a 'pattern or template of expressions' is not a 'sign'. But a signifier, which is a pattern, must be a 'sign', because it is the expression that participates in a designation. But the expression of a fact type form is apparently not a signifier, since only designations have a 'signifier' role, and a fact type form is not a designation. The inconsistency in the terminology, and the failure to make clear parallels and distinctions, is very confusing.

It seems that the idea here is that an 'expression' can be a structure of individual sub-expressions, and that, in representing a fact type, the structure and the sub-expressions play distinct roles in the "actuality" of representing the fact type. This means that at least this idea of structured expressions should be described in clause 8.2, as a kind of expression more interesting than "text".

It appears to be the intent that a fact type form expression always has a structure with representation sub-behaviors. Is that what distinguishes a fact-type form from a designation? The text is completely silent as to what the delimiting characteristic is.

The remaining question then is: what kind of representation is exemplified in a terminological entry for a fact type in the SBVR vocabulary itself? E.g., is "designation has signifier" a designation for a fact type or a fact type form for it? (According to the UML diagram it cannot possibly be both.) And if the latter, does an SBVR fact type not actually have a designation? More confusion.

Recommendation:
1. Define the concept that is "pattern or template of expressions" in 8.2
2. Use these structure concepts to define the nature of a fact type form in 8.3.4. For example, a placeholder is a sub-expression.
3. Specify the distinguishing characteristic of a fact-type form that makes it different from a designation.
4. Specify what the vocabulary entries for fact types are: fact-type forms or fact-type designations.

1. A fact type form is a model of some surface syntax that represents the fact type as a set of grammatical elements. As such the details of a fact type form are irrelevant to the intent of SBVR. Thus, the model in SBVR should involve only those “abstract syntax” elements that are common to all such representations.
2. A fact type form is not a designation – it is a grammatically structured expression serving as a pattern for usage of the fact type designation in some language. A designation for a fact type is a term or symbol that has business meaning, is a vocabulary entry, and may occur in a number of different fact type form structures for the fact type. The designation’ signifier can also be a signifier of designations of other fact types. A fact type form is a usage pattern for a language in which definitions, facts and rules are stated. The text will be revised to make this clear.
3. The glossary headings for fact types in SBVR itself are fact type forms. As specified in Annex C, each terminological entry for a fact type gives a designation for the fact type and the concepts that determine the context in which the signifier of that designation represents that fact type. The text will be revised to make this clear.
4. In order to define ‘fact type form’ as a kind of representation, the text will be revised to refer to an expression that involves signifiers for the fact type and its roles. The modeling of expression syntax is out of scope.