Wednesday, March 31, 2010

Notations Used in Language


Symbol
Stands for...
Σ
Any one character from the alphabet (actually represents a set of all characters in the language)
Σ*
All the string made up from alphabet in Σ
x*
Zero or more repetition of x (where x is one character from Σ)
x+
Once or more repetition of x (where x is one character from Σ)
+
Set union ( a+b, means character present either in set a or set b)
xy
(Juxtaposition) character x followed by character y