# Diskrete Mathematik - Eine Entdeckugsreise (Jiri Matousek and Jaroslav Nesetril): Errata

• p. 5 middle, there are 5 ways to partition the coins: 2+2 was omitted! (Noted by Omar, UIUC)
• p. 77-79, the given definition of the relation f=O(g) is not suitable for situations where g(n)=0 for some values of n. (For example, n=O(n ln n) would not hold according to this definition.) Hence it is better to take the second definition mentioned later, with n_0. (Noted by Konrad Swanepoel.)
• p. 80 Exercise 1, the relation is not a partial ordering because it is not antisymmetric. The right statement should be that the relation is transitive. (Noted by Konrad Swanepoel.)
• p. 210, 3 lines above Prop. 5.3.4, correctly "since a triangle-free graph on 6 vertices has at most 8 edges" (K_{3,3} has 6 vertices, not 9). (Noted by Delphine Hachez)
• Page 371, last displayed formula, m(2m-1)/3-m on the left-hand side should be m(2m-1)/3+m (noted by Hans-Joachim Brenner).
• Page 377, end of the smaller text, Steiner systems are not 1-designs but rather block designs with lambda=1. (This mistake seems to occur only in the German edition.)
• Page 387, Exercise 11.3.4: the statement is false and the solution in the hint is wrong (of course). (Noted by Yuji Odaka).
• Hint to Exercise 2.3.2(b): one should divide into n-r+1 groups, instead or n-r groups. (Noted by M. Suda, Prague)
• Hint to Exercise 10.2.5: (1+x+x^2) should be in the denominator, not in the numerator, and the generalized binomial theorem is not applicable. The exercise would thus be more suitable for the next section. (Noted by J. L. Doncel, Coruna)
• Hint to Exercise 10.3.8: should be (n+1)/2^n (noted by Hans-Joachim Brenner).