The book and class leave it at that and proceed onto the limits of computability, which is the real point of the material. But there’s a natural question that isn’t presented in the book and which I never thought to ask:

Finite State Automata Regular Expressions
Pushdown Automata Context Free Grammars
Turing Machines ?

While we know that there are many models that equal Turing Machines, we could also construct other models that equal FSAs or PDAs. Why are RegExs and CFGs used as the parallel models of computation? With the machine model, we were able to just add a stack to move up at each level – is there a natural connection between RegExs and CFGs that we extrapolate to find their next level that is Turing equivalent?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s