On Fri, 11 Feb 2000 03:24:08 -0800 (PST), Peter Westlake
<peter@harlequin.co.uk> wrote:
>>Am 2000-02-10 um 15:07 h (PST) hat Paul Keinanen geschrieben:
>>> These fractions might be usable in countries using "Imperial" units,
>>> but as far as I know, there are only a few countries still using
>>> "Imperial" units :-).
Please note that I was originally talking about the coding of certain
rational numbers with a special character code, not the usability of
the rational numbers as a whole. While the rational number consists of
two integers and since the number of integers is infinite, so must the
number of rational numbers also be. Thus, I do not see the point of
encoding some selected fractions with special character codes. Even
with integers, I do not know of any writing system that would have a
special symbol for say, 17384, but it is composed of a limited number
of component, quite often (but not always) based on some kind of the
base 10 positional system.
>Why are fractions only usable with Imperial units? Do ISO standards
>forbid metric units to be written as fractions?
While it makes sense to say that one third of six eggs is two eggs,
however, when making measurements, we are always talking about
approximations that are made at some precision. The number of
significant digits in a decimal number is a convenient way of giving
an indication at what precision the measurement has been made without
explicitly specifying the error limits. On the other hand a statement
like "the length of the pole was measured as 22/7 meters" does not
make much sense, since that would indicate an exact entity which would
remain true no matter what precision is available in later
measurements.
>Also, not everything
>is a unit; fractions are very useful in mathematical formulae,
> and for numbers in general.
No argument about that, since the argument was assigning character
code points to some selected rational numbers.
Paul
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