Difference between revisions of "Subset"

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We say a [[set]] <math>A</math> is a '''subset''' of another set <math>B</math> if every [[element]] of <math>A</math> is also an element of <math>B</math>, and we denote this by <math>A \sub B</math>.  The [[empty set]] is a subset of every set, and every set is a subset of itself.  The notation <math>A \subseteq B</math> emphasizes that <math>A</math> may be equal to <math>B</math>, while <math>\displaystyle A \subsetneq B</math> says that <math>A</math> is any subset of <math>B</math> other than <math>B</math> itself.
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We say a [[set]] <math>A</math> is a '''subset''' of another set <math>B</math> if every [[element]] of <math>A</math> is also an element of <math>B</math>, and we denote this by <math>A \sub B</math>.  The [[empty set]] is a subset of every set, and every set is a subset of itself.  The notation <math>A \subseteq B</math> emphasizes that <math>A</math> may be equal to <math>B</math>, while <math>A \subsetneq B</math> says that <math>A</math> is any subset of <math>B</math> other than <math>B</math> itself.
  
  
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=== Intermediate ===
 
=== Intermediate ===
 
* [[1992_AIME_Problems/Problem_2 | 1992 AIME Problem 2]]
 
* [[1992_AIME_Problems/Problem_2 | 1992 AIME Problem 2]]
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[[Category:Set Theory]]

Revision as of 11:10, 3 December 2007

We say a set $A$ is a subset of another set $B$ if every element of $A$ is also an element of $B$, and we denote this by $A \sub B$ (Error compiling LaTeX. Unknown error_msg). The empty set is a subset of every set, and every set is a subset of itself. The notation $A \subseteq B$ emphasizes that $A$ may be equal to $B$, while $A \subsetneq B$ says that $A$ is any subset of $B$ other than $B$ itself.


The following is a true statement:

$\emptyset \sub \{1, 2\} \sub \mathbb{N} \sub \mathbb{Z} \sub \mathbb{Q} \sub \mathbb{R} \sub \mathbb{C} \sub \mathbb{C}\, \cup\{\textrm{Groucho, Harpo, Chico}\} \supset \{1, 2, i, \textrm{Groucho}\}$ (Error compiling LaTeX. Unknown error_msg)


The set of all subsets of a given set $S$ is called the power set of $S$ and is denoted $\mathcal{P}(S)$ or $2^S$.

Example Problems

Introductory

Intermediate