Difference between revisions of "Natural number"

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The natural numbers, denoted by the set <math>\mathbb{N}</math>, is itself a subset of the [[integer]]s <math>\displaystyle\mathbb{Z}</math>, which is a subset of the [[real]]s, <math>\mathbb{R}</math>. The natural numbers can be defined as ''every integer greater than or equal to 1''. Don't confuse this with the [[whole number]]s, starting at 0.
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The set of '''natural numbers''', denoted <math>\mathbb{N}</math>, is a subset of the [[integer]]s <math>\displaystyle\mathbb{Z}</math>.  Unfortunately, exactly which subset is not entirely clear: in some texts, <math>\mathbb{N}</math> is taken to be the set of [[counting number]]s ([[positive integer]]s), while in others it is taken to be the set of [[whole number]]s ([[nonnegative integers]]).  Because of this ambiguity, one should always be careful to define one's notation clearly.  Possible alternatives include <math>\mathbb{P}</math> or <math>\mathbb{Z}_{>0}</math> for the positive integers or <math>\mathbb{Z}_{\geq0}</math> for the non-negative integers.

Revision as of 00:11, 27 June 2006

The set of natural numbers, denoted $\mathbb{N}$, is a subset of the integers $\displaystyle\mathbb{Z}$. Unfortunately, exactly which subset is not entirely clear: in some texts, $\mathbb{N}$ is taken to be the set of counting numbers (positive integers), while in others it is taken to be the set of whole numbers (nonnegative integers). Because of this ambiguity, one should always be careful to define one's notation clearly. Possible alternatives include $\mathbb{P}$ or $\mathbb{Z}_{>0}$ for the positive integers or $\mathbb{Z}_{\geq0}$ for the non-negative integers.