(A) Lemma 2.8: circumference |c_1|+|c_2| = lambda*lambda_(j-2), height sin((j-1)pi/n), modulus 2cot(pi/n): 70151 strips, 3 <= n <= 60: ok
(D),(E) Theorem D: sin(pi/n)sin(2pi/n) >= sin((k+1)pi/n)sin((k+2)pi/n) only for k = 0, n-3 (equality); (lambda^2-2)sin(pi/n) = sin(3pi/n)-sin(pi/n) in (0, sin(3pi/n)): 5 <= n <= 200: ok
(F) Lemma 6.1: a*c_1 = b*c_2 = kappa > 1 for 1 <= k <= n-3; c_1 = lambda^2-1, c_2 = 1 for k = n-3: 5 <= n <= 200: ok
    (6.1): X_(k+1) = a*eta + b*xi with the stated a, b: exact in the ring, 5 <= n <= 16: ok
(G) proof of Theorem F(c): T_1(eta-xi) = w_n = eta-xi+lambda^2 X_(n-2); g_0 xi, g_0 eta; g_0 X_(n-2) = w_n; f_eta values; no admissible i; and T_1 T = -R_(2pi/n) (Lemma 8.11): exact, 5 <= n <= 16: ok
    trace(T R^-1) = 0 and T_1 T = -R_(2pi/n) in floating point, 3 <= n <= 61: ok
(I) Lemma 8.9 from the formulas of Lemma 8.8: <c_i,c_j> = <c'_i,c'_j> = 0, <c'_j,c_i> = -eps_0 [i+j in {m,m+1}], the two sums (8.2): odd n, 5 <= n <= 61: ok
(H) Lemma 8.5(a) and Lemma 8.6: after 2t crossings g_2t(X_a) = c_2t + X_(a+rot) with rot = 2 sum(s_2i - s_2i-1) from the labels of the crossed sides of D_n, and a_* = -rot, tau = c_2t: 2557 unfolded bands (n = 5,6,7,8,9,10,12,15,21): ok
(J) Lemma 8.10(a): the horizontal line in the strip S_j meets the sides e_(j-1) and e_(n-1-j) of P_0; rot(c_j) = 2((j-1)-(n-1-j)) = 4j mod n: ok
(L) Lemma 8.1: trajectories through the midpoint of a side against a neighbour in the same band (floating billiard): 867 cases, 119 with an odd number j_1 of segments: there j_* = 2 j_1, a_* = 2 a_1, double length; for odd n the same factor: ok
(M) Remark 8.4(a), n=6: the regular n-gon through the midpoints of the sides: 1 segment, x_1 = r^(+-1) x_0, factor 6; its neighbours: 2 segments, factor 3; factors of the bands of this class (direction of a shortest diagonal): (3, 1)
(M) Remark 8.4(a), n=8: the regular n-gon through the midpoints of the sides: 1 segment, x_1 = r^(+-1) x_0, factor 8; its neighbours: 2 segments, factor 4; factors of the bands of this class (direction of a shortest diagonal): (4, 4)
(M) Remark 8.4(a), n=10: the regular n-gon through the midpoints of the sides: 1 segment, x_1 = r^(+-1) x_0, factor 10; its neighbours: 2 segments, factor 5; factors of the bands of this class (direction of a shortest diagonal): (5, 5, 1)
(M) Remark 8.4(a), n=12: the regular n-gon through the midpoints of the sides: 1 segment, x_1 = r^(+-1) x_0, factor 12; its neighbours: 2 segments, factor 6; factors of the bands of this class (direction of a shortest diagonal): (6, 2, 6)
ALL CHECKS PASSED
