Apa itu Deflated Sharpe ratio?

For a Sharpe ratio $\widehat{\mathrm{SR}}$ (per period) estimated from $n$ returns with skewness $\gamma_3$ and kurtosis $\gamma_4$, the probability that the true ratio exceeds $\mathrm{SR}_0$ is approximately

The deflated Sharpe ratio (Bailey and López de Prado, 2014) is this probability with $\mathrm{SR}_0$ the expected maximum of $N$ null Sharpe ratios of variance $V$: $\mathrm{SR}_0 = \sqrt V\bigl((1 - \gamma_E)\Phi^{-1}(1 - 1/N) + \gamma_E\Phi^{-1}(1 - 1/(Ne))\bigr)$, $\gamma_E$ the Euler–Mascheroni constant.