In General
Let be an integral domain and the (Archimedean) absolute value on it.
A number in this positional number system is represented as an expansion
- , where
– the radix (or base) with ,
– exponent (position or place)
– digits from the finite set of digits usually with . The cardinality is called the level of decomposition.
A positional number system or coding system is a pair
with radix and set of digits, and we write the standard set of digits with digits as
- .
Desirable are coding systems with the features
- Every number in, e. g. the Gaussian integers, is uniquely representable as a finite code, possibly with a sign.
- Every number in is representable as an infinite code, where the series converges under for, and the measure of the set of numbers with more than one representation is 0. The latter requires that the set be minimal, i. e. .
In this notation our standard decimal coding scheme is denoted by
- ,
the standard binary system is
- ,
the negabinary system is
- ,
and the balanced ternary system is
- .
All these coding systems have the mentioned features for and, and the latter two do not require a sign.
Well-known positional number systems for the complex numbers include the following ( being the imaginary unit):
- , e. g. and
- , the quater-imaginary base, proposed by Donald Knuth in 1955.
- and
- (see also the section Base −1± below).
- , where, and is a positive integer that can take multiple values at a given . For and this is the system
- .
- ;
- , where the set consists of complex numbers, and numbers, e. g.
- .
- , where
Read more about this topic: Complex Base Systems
Famous quotes containing the word general:
“A thing is called by a certain name because it instantiates a certain universal is obviously circular when particularized, but it looks imposing when left in this general form. And it looks imposing in this general form largely because of the inveterate philosophical habit of treating the shadows cast by words and sentences as if they were separately identifiable. Universals, like facts and propositions, are such shadows.”
—David Pears (b. 1921)
“Can a woman become a genius of the first class? Nobody can know unless women in general shall have equal opportunity with men in education, in vocational choice, and in social welcome of their best intellectual work for a number of generations.”
—Anna Garlin Spencer (18511931)