# Extremal Graph Theory (TAC: Vol. I)'' - Typos

This page lists the typographical errors that have been discovered in the Spring 2006 pre-publication version of Extremal Graph Theory, by Douglas B. West (Volume I of The Art of Combinatorics). This page is of interest only to the few persons having a copy of this draft, such as the students in my course and possibly reviewers. Please send any additional contributions to west@math.uiuc.edu. Contributors noted in parentheses (RS = Ryan Stout).

## Mathematical Errors and/or Typos

• p258 - Theorem 3.2.28: The induction step needs a different argument when B is a (k-1)-clique. In this case, we delete all of B, including v, to form H'. Since dH(v)\le k-1, v has exactly one neighbor in H', so we lose only 1 from f(H'). We gain 1 for each vertex of B other than v. Hence f(H)-f(H') = (k-2)-1 = k-3, as needed.
• p282 - Theorem 3.3.25: "missing at u and at v" should be "missing at u, at least n/2 are missing at v"
• p289 - Remark 3.3.48: In the second question, p and \hat p should be interchanged (RS)
• p298 - Proposition 3.4.4: "earlier numbers" should be "earlier neighbors" (RS)
• p299 - Lemma 3.4.5: "Define L' on V(G-v)" should be "Define L' on V(G-x)". Also, "L(v)-c" should be "L(v)-{c}" (RS)
• p301 - before Theorem 3.4.11: "Always K2,n is 2-choosable" should be "Always K2,n is 3-choosable" (RS)
• p317 - second line: "p(G)" should be "pG" (RS)
• p319 - Remark 3.4.40: "W" should be "F" (RS)
• p331 - Example 3.5.15: A close parenthesis is missing in the discussion of odd cycles
• p356 - Theorem 4.1.13 C=>A: "3.2.19" should be "3.2.18 clique". More importantly, "V(G1) to V(G2)" should be "V(G1)-S to V(G2)-S" (RS)
• p358 - Theorem 4.1.17: "if and only" should be "if and only if" (RS)
• p368 - before Theorem 4.1.37: The definition of weakly chordal graphs (no chordless cycle of length at least 5 in G or its complement) should be added here
• p371 - Exercise 4.1.15: "Q(Si)|" should be "Q(Si)}|" (RS)
• p581 - Exercise 5.4.17: "2^{al}" should be "2^{\alpha}"

## Minor Typos

• p237 - Exercise 3.1.3: "??" should be Proposition 3.1.9.
• p266 - Exercise 3.2.21: This duplicates Exercise 3.1.45 and will be deleted.
• p269 - after Definition 3.3.1: "irrevelance" should be "irrelevance" (RS)
• p281 - before Theorem 3.3.25: "to \infty" should be "to \infty)" (RS)
• p284 - Corollary 3.3.31: "Theorem tree'" should be "Theorem 3.3.30"
• p287 - Theorem 3.3.40: "L4con" should be "Lemma 3.3.39"
• p289 - Theorem 3.3.47: "Theorem canonical'" should be "Theorem 3.3.40" (RS)
• p298 - Proposition 3.4.4: "was not been" should be "has not been" (RS)
• p325 - Example 3.5.1: "streamns" should be "streams" (RS)
• p326 - Proposition 3.5.3: "an given point" should be "any given point" (RS)
• p329 - before Lemma 3.5.11: "denumerator" should be "denominator" (RS)
• p330 - Lemma 3.5.13: "Give" should be "Given"
• p354 - Example 4.1.7: "this is meaning" should be "this is the meaning" (RS)
• p356 - Theorem 4.1.13 B=>C: "is clique" should be "is a clique" (RS)
• p444 - Theorem 4.3.92: "of least at least" should be "of length at least"