What are the respective roles of and ? Do we need both, or any of them?

Related tags: , , , , ,

  • 1
    $\begingroup$ I believe the correct solution is to toss an unbiased coin and use the tag "random" if it comes up heads and "randomness" if it's tails. $\endgroup$ Commented Aug 22, 2015 at 12:48

2 Answers 2


We definitely need at least one tag to cover randomized algorithms (that use randomness to do something) and one for random generators (that produce (pseudo)randomness).

For randomized algorithms, we have , and more specific tags such as , , , etc. This seems fine to me.

For random generators, we have a tag and a more specialized tag , as well as . Most uses of are about PRNG. I'm not sure if this tag is warranted on this site, but technically speaking it is a different topic.

Inasmuch as / are warranted, I don't see any possible difference in meaning, only a stylistic choice. I'm for making the main tags since we usually use nouns as tags (“this question is about randomness”). I have no strong feeling as to the ~70 questions with these tags should be disambiguated to one of the two sides of the randomness coin.

  • $\begingroup$ randomness should be for questions about randomness (e.g., how much random bits are needed for an algorithm. How many samples of Bernoulli(p) are needed to in order to sample some distribution P, etc.). Looking at the list of questions now tagged random it seems this tag was used in practice as a synonyms of randomized-algorithm. $\endgroup$
    – Ran G.
    Commented Aug 21, 2015 at 3:04
  • $\begingroup$ @RanG. So you'd say algorithm-analysis+randomness for analysing the number of necessary random bits? Feels wrong, linguistically, but I don't have better idea. $\endgroup$
    – Raphael
    Commented Aug 21, 2015 at 7:56
  • $\begingroup$ @Raphael randomness is wider, and includes in my eyes also primitives like extractors, etc. My main point was that random should not be synonyms of randomness, but instead of randomized-algorithm. $\endgroup$
    – Ran G.
    Commented Aug 21, 2015 at 9:41
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    $\begingroup$ @RanG. I don't think assigning different meaning to an adjective and its noun is reasonable (at least in the context of tagging). Anyway, it seems as if you want to post your own answer. $\endgroup$
    – Raphael
    Commented Aug 21, 2015 at 11:05
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    $\begingroup$ @RanG. I agree that they're not synonyms. I would favour keeping "randomness", removing the "random" tag and individually retagging its 21 questions with whatever is most appropriate for that question. $\endgroup$ Commented Aug 22, 2015 at 12:51
  • $\begingroup$ Given the feedback so far, should we act? $\endgroup$
    – Raphael
    Commented Sep 9, 2015 at 10:20

Similar to other tag combinations, I think we should in addition to Gilles' answer go


tag can be added to disambiguate.

In particular, I think there is little danger of confusing + with ; the latter are rarely random themselves


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