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\frac{\alpha}{p} \frac{F_{x}^{\prime}(\xi)}{H_{x}^{\prime}(\xi)}=\frac{D^{\prime}(\xi)}{D(\xi)\{1+2 G(x, \xi)\}} \leq \frac{D^{\prime}(x)}{D(x)\{1+2 G(x, x)\}}=\frac{D^{\prime}(x)}{D(x)}