That is right, regardless of the unit used, there is a price to pay for missing the unit 0. Thus, it seems to me, illustrating the issue with centuries, as opposed to years, makes my point larger.
PS. Some people still like to eradicate 0 when referring to specific years, including the present year MMXVIII. On Sun, May 20, 2018 at 6:28 PM, 'Bo Jacoby' via Chat <[email protected]> wrote: > "Who cares if you are sometimes off by one year because the year 0 is > missing?". The time from the beginning of the first century BC to the > beginning of the first century AD is one century, while 1-_1=2. Who cares > if you are sometimes off by one century because the century 0 is missing? I > do. Thanks! Bo. > > Den 23:54 søndag den 20. maj 2018 skrev Jose Mario Quintana < > [email protected]>: > > > Historians refer to specific years, using a well-known event as an anchor, > naturally as AD 1, AD 2, AD 3, ... and, going backward, as 1 BC, 2 BC, 3 > BC, ... > > Dropping the AD and inserting a - (_ in J) instead of BC allows for a > simple general consistent rule for calculating the years elapsed between > two dates by subtracting the lower date from the higher date; for example, > the years elapsed between (say, the beginning of) the year _4 and (the > beginning of) the year 30 can be calculated by 30 - _4 ... > > Nevermind, who cares if you are sometimes off by one year because the year > 0 is missing? Presumably, some people who like to date celestial events > precisely : > > Astronomical year numbering > https://en.wikipedia.org/wiki/Astronomical_year_numbering > > PS. There has been some debate about the exact year when the actual > aforementioned event happened: 4 BC, 1 BC, AD 1, ... > > > On Sat, May 19, 2018 at 9:38 AM, 'Bo Jacoby' via Chat <[email protected]> > wrote: > > > The terms "ordinal number" and "cardinal number" has advanced > mathematical > > meanings in the theory of infinite sets and transfinite numbers, but the > > words also have ancient meanings in grammar. The semantics of a cardinal > > number is to count the elements of a finite set, and the semantics of an > > ordinal number is to identify a single element. This century is the > > twentyfirst century. That is a 1-origin ordinal number. The number of > whole > > centuries that have passed so far is 20. That is a 0-origin cardinal > > number. /Bo. > > > > Den 12:49 lørdag den 19. maj 2018 skrev R.E. Boss < > > [email protected]>: > > > > > > > A solution to the problem is to distinguish between the ordinal > numbers > > (first, > > > second, and so on) and cardinal numbers (zero, one, and so on). The > first > > > ordinal number is "first", and the first cardinal number is "zero". > > Cardinal > > > number are for indexing, not for counting. Thanks. Bo. > > > > > > I like that very much, although I read different things in > > https://www.wikiwand.com/en/Ordinal_number > > "A natural number (which, in this context, includes the number 0) can be > > used for two purposes: to describe the size of a set, or to describe the > > position of an element in a sequence." > > (...) > > " Whereas the notion of cardinal number is associated with a set with no > > particular structure on it, the ordinals are intimately linked with the > > special kind of sets that are called well-ordered (...) " > > (...) > > " Ordinals may be used to label the elements of any given well-ordered > set > > (the smallest element being labelled 0, the one after that 1, the next > one > > 2, "and so on") and to measure the "length" of the whole set by the least > > ordinal that is not a label for an element of the set." > > See also https://www.wikiwand.com/en/Cardinal_number . > > > > > > R.E. Boss > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
