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Directory:Jon Awbrey/Papers/Inquiry Driven Systems : Part 6 (view source)
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, 03:32, 26 April 2012→6.7. Basic Notions of Formal Language Theory
===6.7. Basic Notions of Formal Language Theory===
===6.7. Basic Notions of Formal Language Theory===
This section collects the material on formal language theory that is needed for the rest of this work.
This section collects the material on formal language theory that is needed for the rest of this work.
<pre>
A "formal language" is a countable set of "expressions", each of which is a finite sequence of elements taken from a finite set of "symbols". The primitive symbols that are used to generate the expressions of a formal language are collectively called its "alphabet" or its "lexicon", depending on whether the expressions of the language are intuitively regarded as "words" or as "sentences", respectively.
A "formal language" is a countable set of "expressions", each of which is a finite sequence of elements taken from a finite set of "symbols". The primitive symbols that are used to generate the expressions of a formal language are collectively called its "alphabet" or its "lexicon", depending on whether the expressions of the language are intuitively regarded as "words" or as "sentences", respectively.