Definition:Word (Formal Systems)
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This page is about Word in the context of formal systems. For other uses, see Word.
Definition
Let $\AA$ be an alphabet.
Then a word in $\AA$ is a juxtaposition of finitely many (primitive) symbols of $\AA$.
Words are the most ubiquitous of collations used for formal languages.
Also known as
Different treatments of formal languages use different terms for word.
Examples include formula, sentence and string.
However, these alternatives conflict with the concepts logical formula, sentence and string, respectively, in the scope of this site; therefore, their use is discouraged.
It is useful to note that in this context word is a synonym for finite string.
Also see
- Definition:Well-Formed Word: a word in $\AA$ admitted by the formal grammar of some formal language
- Definition:Collation: a generalization of a word as a means to present information in a structured manner
Sources
- 1965: E.J. Lemmon: Beginning Logic ... (previous) ... (next): Chapter $2$: The Propositional Calculus $2$: $1$ Formation Rules (in the context of the language of propositional logic)
- 1979: John E. Hopcroft and Jeffrey D. Ullman: Introduction to Automata Theory, Languages, and Computation ... (previous) ... (next): Chapter $1$: Preliminaries: $1.1$ Strings, Alphabets and Languages
- 1996: H. Jerome Keisler and Joel Robbin: Mathematical Logic and Computability ... (previous) ... (next): $\S 1.2$: Syntax of Propositional Logic