You want 195x to mean "the 1950s"? (Rather than the meaning I had thought we decided on.) Since you are the only one (as far as I know) who cares about the x notation, it's fine with me. --Ray > -----Original Message----- > From: Discussion of the Developing Date/Time Standards > [mailto:[log in to unmask]] On Behalf Of Edward C. Zimmermann > Sent: Tuesday, June 28, 2011 9:31 AM > To: [log in to unmask] > Subject: Re: [DATETIME] On the usefulness of x > > On Mon, 27 Jun 2011 16:57:19 -0400, Ray Denenberg wrote > > > {1950..1959} means the set (all of) dates 1959 through 1959. It is > > > an array of dates expressed with a precision of year. > > > The expression 195x, by contrast, is neither an array nor an > > > expression with a precision of year but a date with a precision of > 10 years. > > > > Are you perhaps confusing 'x' with 'u'? > > No. The expression 195u has a precision of year. It is used to express > a date in year precision where the year, however, is not (yet) known. > The expression, by contast, 195x is of decade precision (10 years) and > does not express any uncertainty. The expression, for example, "The > journal was published in 195u" I would take to imply that it was > published in some year in the 1950s but its uncertain, at this time, > which. The expression, by contrast, "The journal was published 195x" I > would take to mean that the said journal was published in at least one > of the years in the 1950s. > 195u -----------> 1 year in the range 1950 to 1959. The date is > expressed with precision of year. > 195x -----------> 1 or MORE years in the range 1950 to 1959 expressed > with the precision of decade. > > > > > 199u means "one of the years 1990, 1991, 1992, etc." > > 199x is supposed to mean "ALL of the years 1990, 1991, 1992, etc." > > That is the difference in our views and why I think "x" is needed and > can't be replaced by {..} expressions. {1950..1959) can mean ALL of > the years since its an expression of an array of dates with an implicit > measurement precision of year. > If one agrees that the expression "195x" has a precision of decade than > it can't be ALL since that would entail a readability (precision) of > year. > The contruct 'x' (from right to left) I took to represent the > expressions "1950s", 18th Century etc. > The expression 195x (1950s) is, I think, like reading a short > thermometer with ticks every 10 degrees. Its hard to talk about where, > for example, 33 degrees is.. its not readable to degree. > Its, again, like 1999. That expression does not mean "all" days, hours, > minutes or .. If I say that a journal was published in 1999 I mean that > at least one issue (perhaps more) was published in 1999 but not that an > issue was published every second. "1999" means one or more and not ALL. > The expression "1999" has a precision of year so I can't read precisely > month, day, hour, minute, second ... > > > > > The example cited is someone listing years of publication. For > example > > for > a > > book published in 1992, 1996, and 1998 you could list its years of > > publication as {1992, 1996, 1998}. > > > > But say it was published in 1988, 1990, 1991, 1992, 1993, 1994, 1995, > > 1996, 1997, 1998, 1999, 2002, and 2004. > > > > You could list its years of publication as {1988, 199x, 2002, 2004}. > > > > This is what we decided many months ago. > > I did not decide this :-) > I was always, I think, speaking of precision. Wildcards never really > interested me except in queries. That is why I see 195x as being > something to implement (well its been implemented already by me as I > have interpreted > it) but not 1x59. I can see some interesting questions expressable with > wildcards such as "turn of the century", "mid century" etc. but see > them on the side of query and less on the side of date representation > for storage--- I would implement these, just as generalized 'u', in the > query engine (state > machine) and not in my indexer (data storage model). > > > > > --Ray > > > -- > > Edward C. Zimmermann, NONMONOTONIC LAB > http://www.nonmonotonic.net > Umsatz-St-ID: DE130492967