### Errata for "A Walk Through Combinatorics"

• Page 93, last line. Change "side" to "size".

• Page 136, line 3. Change Dn to D(n).

• Page 170, Exercise 26. The recurrence should hold for n greater than or equal to 0 (not 1).

• Page 170, Exercise 32, line 2. Delete the word "form" at the end of the line.

• Page 192, line 16. Change hk to hj (two times).

• Page 192, line 8-. Change G to T.

• Page 194, Figure 9.8. This figure does not match the description in the text describing it. One way to fix it is to relabel E, F, G, H as A, C, B, D, respectively.

• Pages 195-196. The statement that graph isomorphism is NP-complete is not known to be correct. It is a famous open problem.

• Page 196, line 7 of Notes. Change "Pitten" to "Pittel".

• Page 200, Exercise 31. Assume that k>1.

• Page 200, Exercise 32. Change X and Y to x and y, and change dz to dy.

• Page 221, Definition 10.3, and many subsequent places. The term "incidence matrix" is usually used instead of "incidency matrix".

• Page 229, Exercise 22. The statement of this exercise is somewhat ambiguous. The statement should be that all longest paths cross in at least one vertex.

• Page 243, line 3-. Change "minimal" to "maximal".

• Page 258, line 4. Replace p(-1) by (-1)tp(-1), where t is the number of vertices of G.

• Page 278, Supplementary Exercise (11). It should be assumed that V is at least 3.

• Page 279, solution to (1). First, L should be F. More significantly, the reasoning and formula are incorrect. Correct reasoning gives F = E + 2k - V - (k-1) = E - V + k + 1.

• Page 283, Example 13.1. The phrase "three of them who do not know each other" is ambiguous. Does it mean "three of them for which no two know each other" or "three of them for which some two do not know each other"? The former is intended. (If the latter, then the stated result is a tautology.)

• Pages 401-402. Reference numbers are missing (ranging from 1 to 26).