p. 13, exercise #6: the indices a,b,c in the second line should be i,j,k p. 22. Ex. 2.3. a_0 = 1, not a_m p. 50, exercise #17: the word "be" is missing after the b's pp. 54-55, exercise #12: the factorial (!) is missing in numerators, 4 times p. 66, Theorem 4.2: "i=0" on the summation sign should be "k=0" p. 66, Thm 4.2; replace "nonnegative" with "positive" in the statement. p. 67. The ith element of row n, not of row i, is (n choose i). The following five changes are not mandatory (the statement is true as it is, but it will stay true and become stronger if the change is made). ------------------------------------------------------------------------------ p. 66, Thm 4.4; replace "positive" with "nonnegative" in the statement. p. 68, Thm 4.6; replace "positive" with "nonnegative" in the statement. p. 69, Thm 4.7; replace "positive" with "nonnegative" in the statement. p. 69, Thm 4.8; replace "positive" with "nonnegative" in the statement. p. 72, Thm 4.9; replace "positive" with "nonnegative" in the statement. ------------------------------------------------------------------------------ p. 70, Cor 4.1; replace "k >= (n+1)/2 with "k >= (n-1)/2" and also replace "n = 2k-1" with "n = 2k+1". p. 72, Thm 4.9; replace "positive" with "nonnegative" in the statement. p. 73. Line above Theorem 4.11. "This expression" takes the value (m)_n, not (m)_n/n!. You need to use Taylor's Theorem to explain where the 1/n! comes from. p. 90, Thm 5.1; add "For positive integers n and k, ..." to start the statement. p. 90, Cor 5.1; add "For positive integers n and k, ..." to start the statement. p. 90, Cor 5.2; add "For n >= 1, ..." to start the statement. p. 93, Def 5.3; add "We define B(0) = 1." p. 93, Thm 5.3; replace "positive" with "nonnegative" in the statement. p. 99, line -2; should read "Table 5.2". p. 102, Exc. (19); should read "fewer hours". p. 102, Exc. (20); should read "... if n >= 1.". p. 102, Exc. (21); should read "... for all n >= 0.". p. 102, Exc. (22); should read "... for all n >= 0.". p. 102, Exc. (23)a; add "... with k <= n ..." in the hypotheses. (Fails for even k when k > n+1.) p. 112, Line 2 from the bottom, "i different order" should be "i different orders" p. 134, last line of Example 7.3, "different way" should be "different ways" p. 139, Exc. (15); add that the recurrence should be proved for n >= 1, and that D(0)=1 and D(1)=0 p. 147, in the last paragraph (beginning "Finally, we want to"), all references to (8.3) should be to (8.4) p. 148, line 12, delete "for" in the phrase "In general, for if i" p. 168, Exercise (5) should say h_{n+2}=3h_{n+1}-h_n p. 169, Exercise (23) needs an initial condition p. 170, Exercise (26), "if n >= 1" should be "if n >= 0" p. 170, Exercise (32), "then form arrange" should be "then arrange" pp. 180 - 181, the solutions to problems (19) and (20) (p. 169) are in reverse order p.195 It is incorrectly stated that non-isomorphism of graphs is known to be NP-complete. In fact, it is a famous open problem whether non-isomorphism of graphs is NP-complete or not. Page 206, line -7: "\sum_{n\geq0}." -> "\sum_{n\geq0}\frac{2^{n\choose2}x^n}{n!}." p. 220, line -2: "A^k" -> "{n-1 \choose k}A^k" p. 221, line 4: "of A" -> "of G" p. 230, line 13: "+a_n" -> "+a_{n+1}" p.253, Proof of theore 11.6. The sentence starting with "Our conditions.." should read: Our conditions imply that adding an edge to $G$ would create a $K_k$ subgraph. p. 288, second sentence, "k <= 5" should be "k >= 5" p. 307, line -10; should read "larger" instead of "smaller", and "minimum and to the right of it are" instead of "minimum are". p. 344, displayed equation after (15.1), the third expression in the sequence of five should have denominator k! 2^{k choose 2} pp. 355-356, The proof of Example 15.6 appears twice in succession. last paragraph on p. 373: the sets U and L are not disjoint, but have intersection A. second case, p. 374: "Let x be a minimal element of P, and let y be a maximal element of P. Then x <= y." should be "Let x be a minimal element of P and let y be a maximal element of P such that x <= y." (Not all maximal elements y of P satisfy x <= y, but at least one does.)