Talk:Nominal number
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[edit] What is "comparison"?
The article claims that "comparison" is the only valid operator on nominal numbers, and then restricts "comparison" to the equality operator '='. However, don't nominal numbers in practice have a total order on them, resulting in a less-than operator '<'? --Damian Yerrick 17:03, 1 December 2005 (UTC)
- No. Remember that these entities are barely numbers to begin with. The '<' & '>' operators only hold if they were serial numbers. DV8 2XL 17:48, 1 December 2005 (UTC)
- OK, I get the point. I'll continue my question in ordinal number. --Damian Yerrick 20:51, 1 December 2005 (UTC)
[edit] Conversion
DV8 2XL removed the following paragraph from the article and asked me to discuss in talk why I added it:
- If nominal numbers are a string of numerals (such as digits or letters), then additional digitwise operations can be defined on them. For instance, applying some total order on the numbers, such as a lexicographic order on the numerals, allows for collation of the numbers as ordinal numbers. Assigning a numeric value to each distinct numeral allows for calculations on the digits within a nominal number for redundancy checks, such as checksums to determine if the number is valid, that is, to verify its membership in a certain defined set.
If converting nominal numbers to digit strings for use as ordinal numbers is not to be discussed in Nominal number, then neither is converting nominal numbers to digit strings for use in a redundancy check. Would you please also delete that part? --Damian Yerrick 21:53, 1 December 2005 (UTC)
- In a bloody rush I made an bad mistake, I am re-inseting that paragraph and I beg your pardon. An unacceptable act of haste on my part DV8 2XL 22:22, 1 December 2005 (UTC)
- Thank you. --Damian Yerrick 22:26, 1 December 2005 (UTC)
[edit] Reduced and refactored
I have refactored and cut down this article; most of the examples are wrong (telephone numbers and zip codes, for example, have a clear internal structure, and both correllate to externals such as geography and telcos), and two sections of the previous text directly contradicted one another. I've also mentioned that the term "nominal number" appears to be a neologism used in schools, rather than a term used by mathematicians; it may be derived from the term "nominal measurement" (or equivalently, "nominal data") used in statistics; however, statisticians and other mathematicians do not, as far as I know, regard the numbers used in nominal measurement as a special "kind of number", just as a mapping of classes to numbers. [1]
I've also had to reduce/remove/refactor material in serial number by the same contributor, which seemed to assign a mathematical significance to the serial number arithmetic defined in RFC 1982 far beyond that intended by its authors, and contained a substantial verbatim extract from that RFC.
-- The Anome 12:22, 15 January 2006 (UTC)
- I've continued in this vein, indicating that the term has limited use, and distinguishing between a broad sense ("any string used for identification") and a narrow sense ("a string that conveys no information beyond identification"), and given extensive examples.
- Nbarth (email) (talk) 14:34, 1 March 2008 (UTC)
