“…There has been much effort to empirically test the validity of EMH in various markets. Major approaches include using traditional statistical methods such as autocorrelation or cross-correlation [ 5 , 6 , 7 ], variance ratio [ 8 , 9 , 10 , 11 ], the state space model [ 12 ], as well as metrics from complexity science such as Lempel–Ziv complexity (LZ) [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ], permutation entropy (PE) [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ], and Hurst parameter and multifractal measures [ 11 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. The approaches from complexity science are especially appealing as they are fundamentally different from machine-learning-based black-box approaches.…”