# ``Order and Optimization (TAC: Vol. III)'' - Typos

This page lists the typographical errors that have been discovered in the Fall 2009 or Fall 2011 pre-publication version of Order and Optimization, by Douglas B. West (Volume III of The Art of Combinatorics). The typos from 2009 were corrected before 2011, but some typos found in the 2011 edition are mixed in with these. This page is of interest only to the few persons having copies 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.

## Category 1: Corrections of a Mathematical Nature

• p81, Lemma 11.4.21: As in the other results in this portion, the hypothesis should explicitly restrict to distributive lattices (Greg Puleo)
• p85, Theorem 11.4.30: The last character in the second displayed line should be "v", not "u" (Greg Puleo)
• p89, Theorem 11.4.35: Near the end of the first paragraph, "≥" should be ">" (Greg Puleo)
• p156, Lemma 12.3.7: "from the permutations in a realizer" should be "from the extensions in a realizer" (Kyle Jao)
• p206, first paragraph: the base of the logarithm should be 1/δ0 (Kyle Jao)
• p219, before Example 13.1.10: delete "all the sets whose size exceeds n/2 and is at most k" (this is not an antichain)
• p229, Theorem 13.1.30: In the second paragraph, the conclusion B∈H needs B⊆T. This holds by the choice of T; otherwise, a set properly containing T would be the union of disjoint members of I
• p240, Theorem 13.2.3: "under x" should be "under xr" in the second line (Kyle Jao)

## Category 3: Minor Changes, Typos, and Clarifications

• p6, Definition 0.11: "A poset finite" should be "A poset is finite" (Michael Santana)
• p172, Exercise 12.3.8: Repeats Exercise 12.2.15.
• p262, after Theorem 13.3.15: "we seek to minimum" should be "we seek to minimize" (Kyle Jao)