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0 pointsdrdeca12y ago0 comments

If a regex is required to only match x if p(x), is the regex required to match ALL x such that p(x)?

Although this is probably just pointless nitpicking on my part.

0 comments

Of course it is required (within the computational limits of your computer, of course)

If p(x) means 'x is an integer', you could use the regex /^1$/ since it matches integers only (in particular, the integer 1). That's not sufficient, you need to match all integers.

edited:format

algorias12y ago

It's required to match all such x, otherwise the empty regex "" trivially satisfies the requirement.

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