# Relative Word Frequency Function

(Redirected from Term Relative Frequency)

A Relative Word Frequency Function is a relative text item frequency function $\displaystyle{ tf }$ that produces a relative term frequency for some word form $\displaystyle{ w }$ with respect to a word form set $\displaystyle{ D }$.

## References

### 2009

• (Wikipedia, 2009) ⇒ http://en.wikipedia.org/wiki/Tf%E2%80%93idf#Mathematical_details
• The term count in the given document is simply the number of times a given term appears in that document. This count is usually normalized to prevent a bias towards longer documents (which may have a higher term count regardless of the actual importance of that term in the document) to give a measure of the importance of the term $\displaystyle{ t_{i} }$ within the particular document $\displaystyle{ d_{j} }$. Thus we have the term frequency, defined as follows.

$\displaystyle{ \mathrm{tf_{i,j}} = \frac{n_{i,j}}{\sum_k n_{k,j}} }$ where $\displaystyle{ n_{i,j} }$

is the number of occurrences of the considered term ($\displaystyle{ t_{i} }$) in document $\displaystyle{ d_{j} }$, and the denominator is the sum of number of occurrences of all terms in document $\displaystyle{ d_{j} }$.