- From: Leonard Will <L.Will@willpowerinfo.co.uk>
- Date: Wed, 3 Mar 2004 18:20:50 +0000
- To: public-esw-thes@w3.org
In message <350DC7048372D31197F200902773DF4C047485F4@exchange11.rl.ac.uk> on Wed, 3 Mar 2004, "Miles, AJ (Alistair)" <A.J.Miles@rl.ac.uk> wrote > >I designed SKOS to be strictly concept-oriented. In this view there are >only 'concepts' and 'labels'. > >Antonymy: > >In the concept-oriented view, 'antonymy' would be represented as a >relationship between two concepts. So in an imaginary thesaurus, >concept A (label 'Black') is opposite of concept B (label 'White'). As >an extension of SKOS, the relationship 'is opposite of' would be >modelled as a sub-property of skos:SemanticRelation. There are some cases where apparent antonyms are alternative labels for the same concept. "Dryness" and "wetness" for example are both possible labels for the concept of "moisture content". (The "half-full" or "half-empty" situation.) >Equivalence between terms: > >In the concept-oriented view, a label is simply a string. Therefore, there >is no notion of 'equivalence' between labels. > >A label may be used as a label for more than one concept. This worries me. A label is only of use if it identifies the thing it labels. I may have three jars labelled "coffee", of which one contains coffee, one contains tea and the other contains sugar, but this is not the sort of situation we should accept. Did you mean to say that a concept may have more than one label? That is certainly true, and two labels that refer to the same concept could reasonably be said to be "equivalent". >However, a label is always considered to be empty of meaning. >Therefore, there is no notion of 'equivalence' between a label and a >concept. Perhaps not "equivalence" but still a close association. The label is a convenient way of referring to the concept, avoiding the need to write out the scope note in full every time you want to refer to it. If I label a jar "coffee", "café" or "641.3373", those symbols are by no means empty of meaning; they indicate the same substance even though the character strings are not "equivalent" to the substance. >SKOS supports a notion of 'equivalence' between concepts. This may >either be modelled as a sub-property of skos:SemanticRelation (i.e. an >intra-thesaurus relation) or a sub-property of skos-map:SemanticMapping >(i.e. an inter-thesaurus relation). > >E.g. SKOS-Mapping contains the property skos-map:exactMapping, which >could be used to express an 'exact equivalence' relationship between >two concepts. >E.g. SKOS-Mapping contains two properties skos-map:MajorMapping and >skos-map:MinorMapping, which could be used to express greater or lesser >degrees of 'equivalence' between concepts. As you have indicated, equivalence between concepts is something that should arise only when mapping between different thesauri. If two concepts within a single thesaurus are exactly equivalent, I see no need for them both to be present. They should be combined, as there is only one concept, not two. If there is partial equivalence between concepts in a single thesaurus, then either one is a narrower term of the other or else there is an area of overlap (e.g. "ships" and "boats"). In the latter case the scope of each concept should if possible be redefined so as to eliminate this overlap, as it will lead to uncertainty in using the thesaurus. An associative link may then be made between the two related concepts. It must be difficult to differentiate between MajorMapping and MinorMapping, but it is probably helpful to have these to indicate large or small extents of overlap. > >Final word: > >This is how I think of it. To switch from a 'term-oriented' view to a >'concept-oriented' view, instead of 'term' think 'concept+label'. Or 'concept + as many labels as necessary' (of which one may be designated as the "preferred" label or "descriptor"). >What does everyone think? > >Al. My tuppence worth. Leonard -- Willpower Information (Partners: Dr Leonard D Will, Sheena E Will) Information Management Consultants Tel: +44 (0)20 8372 0092 27 Calshot Way, Enfield, Middlesex EN2 7BQ, UK. Fax: +44 (0)870 051 7276 L.Will@Willpowerinfo.co.uk Sheena.Will@Willpowerinfo.co.uk ---------------- <URL:http://www.willpowerinfo.co.uk/> -----------------
Received on Wednesday, 3 March 2004 13:21:27 UTC