Dickman function: Difference between revisions
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{{Orphan|date=November 2006}} | |||
In [[formal language]] theory, a '''picture language''' is a set of ''pictures'', where a picture is a 2D array of characters over some alphabet. | |||
For example, the language <math>L = \left \{ a^{n,n} | n > 0 \right \} </math> defines the language of squares composed of the character <math>a</math>. This language <math>L</math> contains pictures such as: | |||
a a a a <math> \in L </math> | |||
a, a, a a | |||
The study of picture languages was initially motivated by the problems of pattern recognition and image processing, but two-dimensional patterns also appear in the study of cellular automata and other parallel computing models. Some [[formal system]]s have been created to define picture languages, such as array grammars and tiling systems. | |||
==References== | |||
* D. Giammaresi, A. Restivo. [http://www.mat.uniroma2.it/~giammarr/Research/Papers/chap96.ps.Z Two-dimensional languages]. In [[Arto Salomaa|A. Salomaa]], G. Rozenberg (Eds.), ''Handbook of Formal Languages'', Vol. 3, Beyond Words, Springer, Berlin, 1997, pp. 215–267. | |||
[[Category:Formal languages]] | |||
{{formalmethods-stub}} | |||
Revision as of 01:11, 18 January 2014
Template:Orphan In formal language theory, a picture language is a set of pictures, where a picture is a 2D array of characters over some alphabet.
For example, the language defines the language of squares composed of the character . This language contains pictures such as:
a a a a
a, a, a a
The study of picture languages was initially motivated by the problems of pattern recognition and image processing, but two-dimensional patterns also appear in the study of cellular automata and other parallel computing models. Some formal systems have been created to define picture languages, such as array grammars and tiling systems.
References
- D. Giammaresi, A. Restivo. Two-dimensional languages. In A. Salomaa, G. Rozenberg (Eds.), Handbook of Formal Languages, Vol. 3, Beyond Words, Springer, Berlin, 1997, pp. 215–267.