In mathematics of special functions, the Neuman–Sándor mean M, of two positive and unequal numbers a and b, is defined as: This mean interpolates the inequality of the unweighted arithmetic mean A = (a + b)/2) and of the second Seiffert mean T defined as: so that A < M < T. The M(a,b) mean, introduced by Edward Neuman and József Sándor,[1] has recently been the subject of intensive research and many remarkable inequalities for this mean can be found in the literature.
[2] Several authors obtained sharp and optimal bounds for the Neuman–Sándor mean.
[3][4][5][6][7] Neuman and others utilized this mean to study other bivariate means and inequalities.
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