4.1 CLOSURE PROPERTIES OF REGULAR LANGUAGES
Consider the following question: Given two regular languages L1 and L2, is their union also regular? In specific instances, the answer may be obvious, but here we want to address the problem in general. Is it true for all regular L1 and L2? It turns out that the answer is yes, a fact we express by saying that the family of regular languages is closed under union. We can ask similar questions about other types of operations on languages; this leads us to the study of the closure properties of languages in general.
Closure properties of various language families under different operations are of considerable theoretical interest. At first sight, it may not be clear what practical significance these properties ...
Get An Introduction to Formal Languages and Automata, 7th Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
