Talk:Alphabet (formal languages)

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Combine with Symbol[edit]

I recommend that this page be combined with the Symbol page. 97.65.82.66 (talk) 7:11, 8 September 2010

An argument against merging is that the article about "symbol" is fairly general and also covers uses outside the area of computer science. Also, the explanation in Symbol (formal) is not written in the style of a rigorous mathematical definition. In the context of (theoretical) computer science, just pointing to alphabet (computer science) eliminates the need for inlining the mathematical definition every time the term is used. Hermel (talk) 21:48, 13 September 2010 (UTC)
In no way should this be merged with symbol. I suspect that the commenter is not familiar with the huge amount of mathematics that is based on the concept of an alphabet. It's a foundational idea. Jason Quinn (talk) 12:00, 13 July 2011 (UTC)

Title[edit]

I dislike the current title Alphabet (computer science). I think "Alphabet (mathematics)" would be more appropriate. Other opinions? Jason Quinn (talk) 12:02, 13 July 2011 (UTC)

Definition[edit]

I recently changed the definition based on one given in a mathematical logic textbook (Ebbinghaus's Mathematical Logic). This definition agrees with what I usually see in mathematical texts. Logically there is no problem with using an infinite (even uncountable) alphabet. I suspect that at least some computer science texts require an alphabet to be finite by definition. It makes sense to me to use the more general definition in the article and if necessary to qualify statements made in a computer science context. Ebbinghaus also disallows an "empty alphabet" and article now also adopts that since I don't anticipate a problem with this. Correct me if you know better. Jason Quinn (talk) 12:11, 13 July 2011 (UTC)

Alphabets with ambiguous strings[edit]

Suppose an alphabet is the set {|,||} and we are interested in the string "|||". This string is ambiguous and cannot be parsed unambiguously. Does someone here know what the name of this class of "ambiguous" alphabets is called? I am curious about special sub-classes and so forth. Jason Quinn (talk) 12:14, 13 July 2011 (UTC)