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Comment by wtallis | Hacker News Reader

If you assume that pi is a normal number (unproven, but likely) then it is almost certain (ie. probability 1) that the digits of e and the square root of 2 are subsequences of the digits of pi.

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What do you mean by subsequence?

Don't normal numbers only have to contain every finite string often enough, not every infinite string?

http://en.wikipedia.org/wiki/Normal_number

http://mathworld.wolfram.com/NormalNumber.html

http://en.wikipedia.org/wiki/Subsequence

http://mathworld.wolfram.com/Subsequence.html

Does anybody want to explain why they downvoted a mathematical fact?

To answer my questions (according to your links): Yes, normal numbers only have to satisfy conditions on finite strings. And subsequence means deleting some items out of a sequence.

Maybe this was your point, but it seems to me that, with these definition, wtallis's claim (http://news.ycombinator.com/item?id=1567549) is correct; indeed, one simply needs to find 1 at some point, then find 4 a little later, then 1 after that, then 4 again, then a 2, and so forth. The indices where one finds the desired digits become the indices of the claimed subsequence of digits of π.

Indeed. And for the claim to be correct, even a much weaker condition than normality would suffice. E.g. a number like 0.123456789012345678901234567890[repeat] is definitely not normal, but contains all decimal subsequences.

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