[sc34wg3] RM Comment: Connectedness

Patrick Durusau sc34wg3@isotopicmaps.org
Fri, 07 Feb 2003 17:05:41 -0500

RM Comment: "connectedness"

REF: parid0026 parid0932 parid0209


parid0026 reads:  A topic map graph consists of nodes and arcs. In a well-formed topic map graph, every arc is a 
typed, oriented connectedness of two nodes, and every node is one of the two endpoints of zero or more arcs.
parid0932 reads: This RM4TM uses the neologism "connectedness" in order to avoid implying that TM Applications must be
implemented in such a way that arcs are represented as a data structure.  For example, The arc abstraction can be fully
honored by the property values of the nodes that serve as its endpoints.

parid0209 reads: In order to maintain the integrity of merged topic maps, it is necessary to establish a common structure
for all assertions.  In this RM4TM, the decisions as to which aspects of the structure of assertions should be "reified"
as nodes, and which aspects should remain "unreified" as arcs, were made by distinguishing between the aspects of
assertions that are substantive with respect to the relationships that they assert (and that could conceivably,
therefore, need to become role players in other assertions about those relationships), as opposed to the aspects
of assertions that nobody would want to make other assertions about unless they were discussing the design of assertions in
general.  In the structure of assertions set forth in this RM4TM, the former aspects are represented by a-nodes and c-nodes,
while the latter aspects are represented as the four types of arcs (the "eight forms of connectedness")

FIX: reform to remove all references to "connectedness" and replace with relationship/s.

COM: The "neologism" of connectedness appears to serve two purposes: 1. to not necessitate a data structure in a TM
Application and, 2. to distinguish between "aspects of the structure of assertions" (I read as "subjects") that are 
nodes and those that are arcs.

The notion of relationship works as well, provided it is stated that the relationships represented by arcs have no 
subjects, unless reified as nodes, and the relationships represented by nodes do have subjects. Seems simpler to define
 the distinction once and to not coin unfamiliar terms to make the distinction. (On the data structure question, simply 
make the statement that arcs do not imply any particular data structure.)

(Note the term "connectedness" 24 times in the text, at parid0026, parid0932, parid0506, parid0907, parid0058, parid0056, 
parid0061, parid0063, parid0065, parid0067, parid0069, parid0071, parid0073, parid0075, parid0076 (twice), parid0908, 
parid0910, parid0909 (four times), parid0146, parid0209.)

I will be submitting separate comments on each of these paragraphs with suggested new language.



Patrick Durusau
Director of Research and Development
Society of Biblical Literature
Co-Editor, ISO Reference Model for Topic Maps