Editing Unary numeral system (section)

==Applications==
In addition to the application in tally marks, unary numbering is used as part of some data compression algorithms such as [[Golomb coding]].<ref>{{citation
 | last = Golomb | first = S.W. | author-link = Solomon W. Golomb
 | issue = 3
 | journal = IEEE Transactions on Information Theory
 | pages = 399–401
 | title = Run-length encodings
 | url = http://urchin.earth.li/~twic/Golombs_Original_Paper/
 | volume = IT-12
|doi =10.1109/TIT.1966.1053907
 | year = 1966}}.</ref> It also forms the basis for the [[Peano axioms]] for formalizing arithmetic within [[mathematical logic]].<ref>{{citation
 | last1 = Magaud | first1 = Nicolas
 | last2 = Bertot | first2 = Yves
 | contribution = Changing data structures in type theory: a study of natural numbers
 | doi = 10.1007/3-540-45842-5_12
 | mr = 2044538
 | pages = 181–196
 | publisher = Springer, Berlin
 | series = Lecture Notes in Comput. Sci.
 | title = Types for proofs and programs (Durham, 2000)
 | volume = 2277
 | year = 2002| isbn = 978-3-540-43287-6
 }}.</ref>
A form of unary notation called [[Church encoding]] is used to represent numbers within [[lambda calculus]].<ref>{{citation
 | last = Jansen | first = Jan Martin
 | title = The Beauty of Functional Code
 | contribution = Programming in the λ-calculus: from Church to Scott and back
 | doi = 10.1007/978-3-642-40355-2_12
 | pages = 168–180
 | publisher = Springer-Verlag
 | series = Lecture Notes in Computer Science
 | volume = 8106
 | year = 2013| isbn = 978-3-642-40354-5
 }}.</ref>

Some [[email]] [[spam filter]]s tag messages with a number of [[asterisk]]s in an [[e-mail header]] such as ''X-Spam-Bar'' or ''X-SPAM-LEVEL''. The larger the number, the more likely the email is considered spam. Using a unary representation instead of a decimal number lets the user search for messages with a given rating or higher. For example, searching for '''****''' yield messages with a rating of at least 4.<ref>{{citation | url=http://answers.uillinois.edu/illinois/page.php?id=49002 | title=Email, Spam Control, How to get service for departmental email servers }}</ref>