# Errata in the Textbook

This is a list of errors discovered in Dave's draft textbook Discrete Mathematics: A Foundation for Computer Science, Chapters 1-5, 9, 14, and 15, as printed for CMPSCI 250 this term. This is the two-volume set with blue covers, course packet 19 from Collective Copies. If you have the green volumes from Fall 2010, you will also need to look at the errata page from last term.

### Volume I: Chapters 1-4 and Solutions

• Page 1-4, last Definition: Add "We say that A is a proper subset of B if A ⊆ B and A ≠ B."

• Page 1-7, Problem 1.1.1: Parts (b) and (c) use the union and intersection symbols, which are not defined until Section 1.5.

• Page 1-12, line 2 of last Example: "the set NZ of all nonempty strings..." -- the correction is needed because the empty string does not begin with 0.

• Page 1-13, first line: "Note that all the strings in E are in the language NZ as well, because the standard string representing a natural has no leading zeroes. So the string 002 is not in E even though it in some way represents the even natural 2."

• Page 1-23, second full paragraph: This should say "Figure 1-3 is a truth table for the compound proposition ¬p." and the second sentence should be deleted. OR Figure 1-3 on page 1-24 should be adjusted to match this paragraph.

• Page 1-64, Exercise 4: Add a ")" before the "∧" in the next to last line of the exercise.

• Page 1-66: add entry for "proper subset" referring to page 1-4.

• Page 3-5: The text says that n = 30 in Figure 3-2, but n = 36.

• Page 4-30: in Problem 4.6.3, add the additional condition that C(a,b,m) is false whenever b ≥ m.

### Volume II: Chapters 5, 9, 14, 15 and solutions

• Page 9-39: In the second paragraph of subsection 9.9.2, the heuristic should be a lower bound on the actual shortest-path distance from v to t, not from s to t as it says. In the following paragraph, h(v) should not be larger than h(u) + d(v, u), not than h(u) + d(u, v) as it says.