Difference between revisions of "Combinatorics"
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== Introductory combinatorics == | == Introductory combinatorics == | ||
| − | The two most basic and fundamental ideas are that of [[permutations]] and [[combinations]]. | + | The two most basic and fundamental ideas are that of [[permutations]] and [[combinations]]. |
| + | In essentials, the permutation is the number of ways to create a subset of a larger set if order matters (i.e. A, B, C is different from A, C, B). | ||
| + | Similarly, the combination is the number of ways to create a subset of a larger set if order does NOT matter (i.e. A, B, C is the same as A, C, B). | ||
== Intermediate combinatorics == | == Intermediate combinatorics == | ||
An important result of counting techniques is the formulation of the [[Principle of Inclusion-Exclusion]] (PIE). | An important result of counting techniques is the formulation of the [[Principle of Inclusion-Exclusion]] (PIE). | ||
Revision as of 21:51, 17 June 2006
Combinatorics is the study of counting.
Introductory combinatorics
The two most basic and fundamental ideas are that of permutations and combinations. In essentials, the permutation is the number of ways to create a subset of a larger set if order matters (i.e. A, B, C is different from A, C, B). Similarly, the combination is the number of ways to create a subset of a larger set if order does NOT matter (i.e. A, B, C is the same as A, C, B).
Intermediate combinatorics
An important result of counting techniques is the formulation of the Principle of Inclusion-Exclusion (PIE).
