“…The study of the convexity/concavity with respect to Hölder means, or simply H p;q -convexity/concavity, of special functions has attracted attentions of many researchers, see [2,6,7,[9][10][11][13][14][15][16][17]. In particular, the convexity/concavity of the inverse hyperbolic tangent and sine functions has been studied in [9] and [11], respectively.…”