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Viewing Version 4 of 'recurrence relation'
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Title of object: recurrence relation
Canonical Name: RecurrenceRelation
Type: Definition

Created on: 2001-11-04 07:20:20
Modified on: 2005-11-27 03:01:43

Creator: rspuzio
Modifier: Wkbj79
Author: rspuzio
Author: akrowne

Classification: msc:11B37, msc:03D20
Synonyms: recurrence relation=difference equation

Revision comment (for changes between this and next version):

added example
edited paragraphs (indenting was off in page images mode)

Preamble:

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Content:

A \emph{recurrence relation} is an equation which gives the value of an element of a sequence in terms of the values of the sequence for smaller values of the position index and the position index itself. If the current position $n$ of a sequence $s$ is denoted by $s_n$, then the next value of the sequence expressed as a recurrence relation would be of the form

$$ s_{n+1} = f(s_1,s_2,\ldots,s_{n-1},s_n,n) $$

where $f$ is any function. An example of a simple recurrence relation is

$$ s_{n+1} = s_n + (n+1) $$

which is the recurrence relation for the sum of the integers from $1$ to $n+1$. This could also be expressed as

$$ s_n = s_{n-1} + n $$

keeping in mind that as long as we set the proper initial values of the sequence, the recurrence relation indices can have any constant amount added or subtracted.