MaximalElement( U )
MaximalElement returns the ag word in U with maximal exponent vector.
Let G be the parent group of U with canonical generating system (g_1, ..., g_n) and let (u_1, ..., u_m) be the canonical generating system of U, d_i is the depth of u_i with respect to G. Then an ag word u =g_1^{nu_1}* ...* g_n^{nu_n} in U is returned such that sum_{i=1}^m nu_{d_i} is maximal.
GAP 3.4.4