Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== Regular languages ====== $$(-+\Lambda) D D^{\ast} (\Lambda+.D^{\ast}), D \ \text{stands for digit}$$ Basis: $$\emptyset, \{\Lambda\} \text{ and } \{a\} \text{ are regular languages for all } a \in \Sigma$$ The basis of the definition gives us the following for regular languages over the alphabet $\Sigma = \{a,b\}$ **All** regular languages $\Sigma$ can be built from combining these four in various ways by **recursively using the union, product and closure operation**. * $\{\Lambda,b\}$ is regular: $\{\Lambda\} \cup \{b\} = \{\Lambda, b\}$ Any finite languages is easy to build in this way $\implies$ **All finite languages are regular!** theocs/lecture3.txt Last modified: 2024/10/10 12:22by tami