Difference between revisions of "Element"

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<math>A=\{1,\,2,\,3,\,4\}</math> means set <math>A</math> contains the elements 1, 2, 3 and 4.
 
<math>A=\{1,\,2,\,3,\,4\}</math> means set <math>A</math> contains the elements 1, 2, 3 and 4.
  
To show that an element is contained within a set, the <math>\in</math> symbol is used. If <math>A=\{2,\,3\}</math>, then <math>2\in A</math>.
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To show that an element is contained within a set, the <math>\in</math> symbol is used. If <math>A=\{2,\,3\}</math>, then <math>2\in A</math>. The opposite of <math>\in</math> is <math>\notin</math>, which means the element is not contained within the set.
 
 
The opposite of this would be <math>\notin</math>, which means the element is not contained within the set.
 
  
 
=== Sets as Elements ===
 
=== Sets as Elements ===

Revision as of 15:50, 16 April 2008

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An element, also called a member, is an object contained within a set or class.

$A=\{1,\,2,\,3,\,4\}$ means set $A$ contains the elements 1, 2, 3 and 4.

To show that an element is contained within a set, the $\in$ symbol is used. If $A=\{2,\,3\}$, then $2\in A$. The opposite of $\in$ is $\notin$, which means the element is not contained within the set.

Sets as Elements

Elements can also be sets. For example, $B = \{1,\,2,\,\{3,\,4\}\}$. The elements of $B$ are $1$, $2$, and $\{3,\,4\}$.

See Also