Number

One Number (Adj.: numerically) the representation is one or a similar character sequence, which becomes related particularly the marking of objects. It concerns one Numbering. "number" becomes colloquial also as crude name for one experience also related.

Examples of numbers are:

• License number, , (telephone number, fax number)
• Starting number or Back number with the sport
• current chapter number in a text, number of the expenditure of a magazine
• Single presentation one -, or (serial-number in the program)
• those
• a chemical element (nuclear charge number)

Numbering

With one Numbering become all elements a quantity of objects with (usually sequential) Numbers provided. In the many cases is clear the numbering, so that it itself with the numbers over acts. Examples of numberings are , Back numbers with crew kinds of sport. is a less fitting example, since the districts of delivery and postal zip codes were created together; during most numberings the objects are already present against it and with numbers are only provided, in order to be able to refer more simply to it. A substantial characteristic of a numbering is that each number is assigned at the most to a clear object - the reverse case that an object has several numbers, is less problematic, although rather the exception.

The assigned numbers can serve at the same time for it, the objects into one Sequence to bring ( and production of one (numbers as with meaning)

Mathematical definition of a numbering

A numbering leaves itself also mathematical as over one . A numbering of a quantity <math>M</math> thereby one possibly is surjektive Function <math>\nu:\subseteq \mathbb{N} \to M</math>. One assigns M</math> for all <math>m \in; a number <math>n \in \mathbb{N}</math> with <math>\nu(n) = m</math>. All numbers do not have are assigned and <math>m \in a M</math> may also several numbers have.