# Feanor

Krakow, Poland

Age: 25

 1d awarded Commentator 1d comment On mutual tactical serial upvotes and unconstructive commentsJust to play the devil's advocate... Suppose that for whatever reason, person A likes looking at person's B answers. I can imagine a number of ways this could happen, e.g. by similarity of tastes, knowing one another in real life, etc. Nothing wrong with that, I guess. Once A reads X's answer (where maybe X=B, but could also be anyone), he should presumably upvote or downvote, probably upvote more often. And so he does. I agree that this does produce very fair distribution of votes, but we have worse biases than that (e.g. over-voting elementary questions). Sep 13 comment How to check if a sequence is random?Of course, I do not have such black box, but if I did, I think this would result in the type of algorithm in the question. At least, I would be able to account for all "random" sequences you can think of (as long as they are computable). In more down-to-earth terms, I could also do the same without the black box, instead iterating over all Turing machines corresponding to "simple" mathematical constructions (i.e. ones that are bound to stop for "simple" reasons). Sep 13 comment How to check if a sequence is random?I don't actually want to prove a sequence random - I am well aware that this would be impossible. What puzzles me is if I can prove a sequence fails to be random, whenever it fails to be random. Imagine for a moment that I have another black box, which tells me if a given Turing machine produces a 0/1-valued sequence. If I had that, I could devise an algorithm which iterates over all such Turing machines. For each Turing machine I wait until either $a_n$ differs from the output, or I am reasonably sure $a_n$ agrees with the output more than a random sequence would. Sep 13 comment How to check if a sequence is random?Well, I can think of one statistical test I might try that discovers this sequence. Namely, just produce the sequence you mentioned, and check if $a_n$ is equal to $n$-th term of your sequence. Of course, this is a rather obscure test, but I can afford to iterate over similarly obscure tests and see what happens. Sep 12 revised How to check if a sequence is random?added 146 characters in body Sep 12 comment How to check if a sequence is random?When I said "a sequence" I meant "an infinite sequence". They are not deterministic in this sense. Sep 12 asked How to check if a sequence is random? Sep 11 awarded Critic Aug 27 comment Smallest value taken by a quadratic polynomial in two variables.Thank you! I made an error in the formulation, corrected now. In the context I have in mind the "leading" quadratic form is guaranteed to be indefinite anyway, and I was a bit sloppy at this point as a result. Aug 27 revised Smallest value taken by a quadratic polynomial in two variables.added 31 characters in body Aug 26 revised Smallest value taken by a quadratic polynomial in two variables.edited title Aug 26 asked Smallest value taken by a quadratic polynomial in two variables. Aug 26 comment $L^{\infty} (X, \mu)$ is not separable?@Shone: In saying that $\lVert f_A - f_B \rVert = 1$. Otherwise, the norm would be $0$ if e.g. $A = \emptyset$ and $B = \{n\}$ where $\mu(X_n) = 0$. Aug 25 awarded Supporter Aug 22 awarded Yearling Aug 22 awarded Yearling Aug 21 awarded Notable Question Aug 18 awarded Electorate Jul 21 comment What is ethics really about? (the goal or the means)Your claim strikes me as false. Suppose I say that world peace would be a good thing. I can make sense of this statement without first figuring out how to stop all wars, so here is a goal that can be understood with no reference to means. Or I could tell a child (and a god could tell a person, presumably) how to behave, and it would then know the means without knowing the goal. What am I missing?