All entries in the following list refer to the fifth edition. (For a list for the 4th edition, see here.) Any additional comments are welcome.

Page	Line	Comment
18	41	We assume, w.l.o.g., that E(P) is not a subset of E(Q) (otherwise exchange P and Q).
32	4	Replace W_1 by v_1.
32	11	Replace v by v_1.
124	2	Replace $C=\{...\}$ by $C$. The rows of the matrix $A$ in the Hint are $a_1,...,a_t$.
127	36-39	The paper by Dadush, Dey and Vielma [2011] appeared in Mathematical Programming A 145 (2014), 327-348.
186	26	Orlin [2013] found an $O(mn)$-time algorithm for the Maximum Flow Problem. Reference: Orlin, J.B. [2013]: Max flows in $O(nm)$ time, or better. Proceedings of the 45th Annual ACM Symposium on Theory of Computing (2013), to appear
206	40	The correct page numbers of the paper by Cheung, Lau and Leung [2011] are 197-206.
245	27	The coordinates should be independent.
267	1	Replace k by n.
362	30	The proof should begin with the following: Without loss of generality, $f(\emptyset) = g(\emptyset)$ and $f(E) = g(E)$.
371	23	The algorithm finds a maximal element $F$ of $\mathcal{F}$ with $c(F)$ maximum.
372	13	c should be strictly positive in Exercise 8.
378	-3,-2	Replace Ĺ by Φ. Same on page 379, lines 2, 8, and 34, page 381, line 2, page 384, line 31, page 390, lines 4 and 20, page 391, line 18, and page 407, line -3.
503	14	Replace $O(|E(H)|)$ by $O(\log |E(H)|)$.
519	4	The paper by Kawarabayashi, Kobayashi and Reed [2010] appeared in the Journal of Combinatorial Theory B 102 (2012), 424-435.
523	37-38,40	The definition of $q(U\cup\{x\},x)$ is not good, as Lemma 20.4(a) may not hold in general. To fix this, one can either require (w.l.o.g.) $c$ to be a metric or, easier, redefine $q$ as follows: $q(U\cup\{x\},x) := \min \{ c(E(S'))+c(E(S'')) : \emptyset \not= U'\subset U, S' is a Steiner tree for U'\cup\{x\} in G, S'' is a Steiner tree for (U\setminus U')\cup\{x\} in G \}$. Then (a) is trivial, and the proof of (b) is essentially unchanged.
526	30-32	The Steiner tree inapproximability bound was improved to 1.01 by Chlebík and Chlebíková [2008]. Reference: Chlebík, M., and Chlebíková, J.: The Steiner tree problem on graphs: Inapproximability results. Theoretical Computer Science 406 (2008), 207-214
549	30-31	Replace $\le$ by $\ge$ and one $\delta_G(A)$ by $\delta_G(B)$ in both lines.
554	19-21	The paper by Byrka et al. [2010] appeared in the Journal of the ACM 60 (2013), Article 6, with the title: Steiner tree approximation via iterative randomized rounding.
562	6-7	The TSP inapproximability bound was improved to 185/184 by Lampis [2012]. Reference: Lampis, M. [2012]: Improved inapproximability for TSP. Approximation, Randomization, and Combinatorial Optimization; Proceedings of the 16th APPROX Workshop 2012; LNCS 7408 (A. Gupta, K. Jansen, J. Rolim, R. Servedio, eds.), Springer, Berlin 2012, pp. 243-253
591	13-14	The paper by Fiorini et al. [2011] appeared in the Proceedings of the 44th Annual ACM Symposium on Theory of Computing (2012), 95-106.
617	7	"element of" should be "subset of".
627	47-50	The paper by Li [2011] appeared in Information and Computation 222 (2013), 45-58.

Last change: July 10, 2014. Thanks to Steffen Böhmer, Ulrich Brenner, Stephan Held, Stefan Hougardy, Jens Maßberg, Jan Schneider, and Sophie Spirkl.