Wikipedia:Reference desk/Archives/Mathematics/2013 December 30

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December 30

Random in Set Theory Formulas

I am trying to add some proper formulas to a paper. This particular section is best represented as set theory, although the paper is on probability. As a simplistic formula, I want to write that given a set of sequences P, each sequence p in P is a sequence of elements p_1 through p_n. I want to make a set r such that r contains a random element from each p in P. How do I represent "random" in a formula for this? Should it be notated as "p_x:x is a random value from 1 to n"? 209.149.114.201 (talk) 14:29, 30 December 2013 (UTC)

You could represent x as a random variable: a function on a sigma algebra with values in the integers from 1 to n. Sławomir Biały (talk) 15:32, 30 December 2013 (UTC)

Thanks. I think I will have to abandon this. I do not think it is possible. For example, I have to write: A set of s results will be returned such that the first element of the result set will be the most common result found in a set of ordered result sequences such that the result used in each sequences follows an exact subsequence referred to as u. I do not believe it is possible to state "exact subsequence match" or "follows an exact subsequence match" or "most common element of a set" using standard notation. Along with the need for random elements, I think that using standard English will be better than attempting to misuse set theory. 209.149.114.201 (talk) 18:04, 30 December 2013 (UTC)