“…G + n = DC 4n . By results in[27], a minimal genus g ≥ 2 for S is obtained when O has either signature (a) (0; 4, 4, 2n), for n even or (b) (0; 4, 4, n), for n odd. So, ∆ has signature (0; +;[4]; {(m 3 )} and presentation ∆ = β 1 , c 10 , c 11 , e 1 : β 4 1 = c 2 1 j = (c 10 c 11 ) m 3 = 1, e −1 1 c 10 e 1 c 11 = 1, β 1 e 1 = 1 .…”