However, this method for generating means is not general enough to capture all averages. A more general method for defining an average takes any function g(x1, x2, …, xn) of a list of arguments that is continuous, strictly increasing in each argument, and symmetric (invariant under permutation of the arguments). The average y is then the value that, when replacing each member of the list, results in the same function value: g(y, y, …, y) = g(x1, x2, …, xn). This most general definition still captures the important property of all averages that the average of a list of identical elements is that element itself. The function g(x1, x2, …, xn) = x1+x2+ ··· + xn provides the arithmetic mean. The function g(x1, x2, …, xn) = x1x2···xn (where the list elements are positive numbers) provides the geometric mean. The function g(x1, x2, …, xn) = −(x1−1+x2−1+ ··· + xn−1) (where the list elements are positive numbers) provides the harmonic mean.

Oleg Fesov was discovered at the huge ""Садои Осиё"" festival in Alma Ata, Kazakhstan. His international exposure came when German label Blue Flame released a series of recordings with the top performers that participated in that festival. American audiences found out about Oleg Fesov in 1995, when one of his songs, Marav, was included in the three-CD world fusion boxed set titled Planet Soup (Ellipsis Arts CD 3450), released by Ellipsis Arts and produced by Angel Romero.

On 2 March 2016, Matthias Schoenaerts was announced in the cast, reteaming with Vinterberg after Far from the Madding Crowd (2015). Colin Firth joined the cast on 26 May 2016. Léa Seydoux joined the cast on 7 February 2017, in the role of Tanya, the wife of Mikhail Kalekov, a Russian Navy captain-lieutenant played by Matthias Schoenaerts. Rachel McAdams was once in talks for the role of Tanya. Deadline.com also reported that Firth will play David Russell, a British naval commander who goes against Russia’s warnings so he can try to save the men on the Kursk.