Re:A regular expression to check for prime numbers
by kaba0 on Wednesday June 21, 2023 @05:46AM
(#36416448)
> The machine I'm using to type this comment is also a finite state machine, as due to having non-infinite memory, it also cannot count arbitrarily high
Come on, can we drop this useless trivia that floats around? No, computers are Turing-machines for all practical purposes and no the memory is not the tape, unless your computer is sandboxed from everything. As soon as it has some side effect channels, its “tape” can be as large as needed. For example, it can use the internet to store petabytes of state. But if we want to be more pedantic, it can control and observe physical things, making the whole universe its state space.
Which is still finite, so yeah, even more pedantically you are right due to mathematical infinity not existing, but the actual distinction of a Turing machine is “lazy”, if you don’t hit the limit, you may as well reason as if it were a Turing machine.
Come on, can we drop this useless trivia that floats around? No, computers are Turing-machines for all practical purposes and no the memory is not the tape, unless your computer is sandboxed from everything. As soon as it has some side effect channels, its “tape” can be as large as needed. For example, it can use the internet to store petabytes of state. But if we want to be more pedantic, it can control and observe physical things, making the whole universe its state space.
Which is still finite, so yeah, even more pedantically you are right due to mathematical infinity not existing, but the actual distinction of a Turing machine is “lazy”, if you don’t hit the limit, you may as well reason as if it were a Turing machine.