Editing Binary logarithm (section)

===Information theory===
The number of digits ([[bit]]s) in the [[binary representation]] of a positive integer {{mvar|n}} is the [[Floor and ceiling functions|integral part]] of {{math|1 + log<sub>2</sub>{{hsp}}''n''}}, i.e.<ref name="sw11"/>

:<math> \lfloor \log_2 n\rfloor + 1. </math>

In information theory, the definition of the amount of [[self-information]] and [[information entropy]] is often expressed with the binary logarithm, corresponding to making the bit the fundamental [[Units of information|unit of information]]. With these units, the [[Shannon–Hartley theorem]] expresses the information capacity of a channel as the binary logarithm of its signal-to-noise ratio, plus one. However, the [[natural logarithm]] and the [[Nat (unit)|nat]] are also used in alternative notations for these definitions.<ref>{{citation|title=Information Theory|first=Jan C. A.|last=Van der Lubbe|publisher=Cambridge University Press|year=1997|isbn=978-0-521-46760-5|page=3|url=https://books.google.com/books?id=tBuI_6MQTcwC&pg=PA3}}.</ref>