2
Language and Grammar
2.1 BASIC TERMINOLOGY AND DEFINITIONS
Q. Define symbol, alphabet and string.
Ans. Symbol: A symbol is a user-defined entity.
Alphabet: An alphabet is a finite set of symbols denoted by Σ in automata. Alphabets are a set of symbols used to construct a language. Example, {0, 1} is binary alphabet, {A…, Z, a…z} is the alphabet set for the English language.
String: A string is defined as a sequence of symbols of finite length. A string is denoted by w in automata. Example, 000111 is a binary string.
(Length of a string w is denoted by |w|. For the previous case, |w| = |000111| = 6).
Q. Define Prefix, proper Prefix, Suffix, proper Suffix, and substring in relation to a string.
Ans. Prefix: The prefix of a string is the string ...
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