We try to keep our books accurate, but sometimes mistakes creep in. This page lists the errors submitted by our astute readers. If you've found a new error, please submit it.

The latest version of the book is P1.0, released 9 months ago. If you've bought a PDF of the book and would like to upgrade it to this version (for free), visit your home page.

Key: Typo Tech. Error Suggestion Not a problem Next edition

By default this page displays the errata for the latest version of the book. If you have a previous version, select it here:  

(To find out what version you have, look at the copyright page, a few pages in from the front of the book. If it says (say) 'Second Printing', then here it'll be P2.0. If there are interim PDF releases in that printing, they'll be 2.1, 2.2, and so on.)

PDF Paper Description Found in Fixed in
4
#52334: Page 4 of preview chapter irrationals.pdf: "According to legeng" -> legend Page 5 "...consists of a string of 0s and 1s where for digit x...more...
P1.0
07-Aug-13
5
#52303: The subset statement N_2 [subset] N (Section "Cantor's diagonalization"; I'm reading the sample pages, so I cannot give a page number) ...more...
B1.0
02-Aug-13
6
#52336: Page 6 of preview chapter irrationals.pdf "Since the value of e^(i*pi) is not transcendental — it’s 1 — then pi must be transcendental." T...more...
P1.0
07-Aug-13
7
#52059: At the bottom of the page, in step 1, below 'So we can substitute that in and get this:' it should be after the equal sign: (n + 1)(n + 2) / 2...more...
B6.0
24-Jun-13
7q
#52333: States: n(n+1) (n+1)(n+2) ------ + n + 1 = ---------- 2 n should be: n(n+1) (n+1)(n+2) ----...more...
P1.0
07-Aug-13
7
#52339: In the equation on the bottom of the page, under "So we can substitute that in and get this:" shouldn't the right hand denominator be a 2 rath...more...
P1.0
07-Aug-13
7
#58790: Peano induction rule proof for "Summation of N+1 natural numbers", the error is on the last line of the page on the right hand side divided by...more...
P1.0
03-Jan-14
7

#52417: Bottom of page
n(n + 1)/2 + n + 1 = (n + 1)(n + 2) / n

shouldn't that be
n(n + 1)/2 + n + 1 = (n + 1)(n + 2) / 2
--Philip Martel

P1.0
18-Aug-13
7

#52476: In the right side of last formula in Chapter 1 p.7 the denominator of the fraction should be 2 instead of n.

P1.0
27-Aug-13
10
#52337: Page 10 of cantor.pdf [...] D(x,y) returns the yth digit of the decimal expansion of R(x) [...] D(x,3) is the third digit of the binary exp...more...
P1.0
07-Aug-13
12 xii
#52345: There are two nearly identical sentences on this page: "I figured that I’d probably get a couple of dozen people to read it and that I’d pr...more...
P1.0
08-Aug-13
13
#53268: This doesn't seem correct to me: The definition of subtraction turns out to be pretty neat. 3–5 would be (3,0)–(5,0),which is equal to (3,0...more...
P1.0
03-Dec-13
15
#52583: Bit of a nitpick but... The third paragraph starts as follows "There are a couple of ways to describe the real numbers. I’m going to take y...more...
P1.0
05-Sep-13
18+19
#76456: The field axioms are already valid for the rational numbers, and the ordering as well. Both are not specific for the real numbers. Really new ...more...
P1.0
28-Feb-14
20
#53117: (My book version reads "P1.0--July 2013" and as such is not listed on the erratum entry page under "Version of Book With Error".) Shouldn't...more...
P1.0
06-Nov-13
20 6
#52352: This was confusing to me: Recursion For any natural numbers m and n, m + s(n) = s(m + n) ... It’s easier to read if you just rewrite...more...
P1.0
09-Aug-13
20
#52453: The 3th point of: • “≤” is compatible with “+” and “×”: 1. If x ≤ y then (x + 1) ≤ (y + 1). 2. If x ≤ y, then for all z where 0 ≤ z, (x ×...more...
P1.0
25-Aug-13
21
#53094: the last equation on that page has the right hand side with a denominator of 'n', whereas I believe it should be '2'. Otherwise the rest of th...more...
P1.0
30-Oct-13
24

#76457: A small omission: "There's no finite sequence of ... and roots _with only integer numbers_ that will give you the value of a transcendental number."--Dr. Gerhard Nehmiz

P1.0
28-Feb-14
50
#52419: The description of electrical power is wrong. The power does turn on and off. If you apply AC to a resistive load, you can detect the change...more...
P1.0
19-Aug-13
72
#53143: (My book version reads "P1.0--July 2013" and as such is not listed on the erratum entry page under "Version of Book With Error".) Shouldn't...more...
P1.0
12-Nov-13
72
#53148: (My book version reads "P1.0--July 2013" and as such is not listed on the erratum entry page under "Version of Book With Error".) Shouldn't...more...
P1.0
13-Nov-13
73

#58777: Since PI = 3.141592653589793..., a more accurate statement would be that our continued fraction is accurate to 9 decimal places, not 11.--Heinz Kabutz

P1.0
30-Dec-13
73
#52418: "Adding a single convergent to a continued-fraction approximation adds more information than adding a single digit." Not always true. The a...more...
P1.0
18-Aug-13
95
#52944: In the explanation of Step 2, you used the "Or negation" rule, not "And negation". Also in the table of rules you have two labeled "Or Negatio...more...
P1.0
17-Sep-13
99
#52467: In figure 1, the first line of the truth tree has (sorry, I can't copy the symbols) not((A impl B) and (B impl C)) impl (A impl C) To be t...more...
P1.0
26-Aug-13
130
#53269: The symbol you're using for equivalence in the definition of set union and subsequently throughout the book looks wrong. It's used consistentl...more...
P1.0
03-Dec-13
131
#52468: So Parent is a subset of the values from the Cartesian product of the set of people with itself. (Mark, Rebecca) ∈ Parent, and Parent is a p...more...
P1.0
26-Aug-13
140
#52475: The Axiom of Extensionality ∀ A, B : A = B ≨ (∀ C : C ∈ A ⇒ C ∈ B) This is a formal way of saying that a set is described by its members: t...more...
P1.0
27-Aug-13
141

#52532: but we had no way of creating a set containing
both the empty set and the set containing the empty set
({∅, {∅}).

Missing '}' before ')'.--Philip Martel

P1.0
31-Aug-13
142
#52533: Axiom of infinity ∃ N : ∅ ∈ N ∧ (∀ x : x ∈ N ⇒ x ∪ { x } ∈ N) It's probably ok as written, but since you haven't specified an operator pre...more...
P1.0
31-Aug-13
148
#52531: But it implies something absolutely crazy: the well-ordering theorem says that there’s a single, unique value that is the smallest positive ...more...
P1.0
31-Aug-13
157
#52534: The natural number 0 will represent the integer 0; 0 is even, because 0 * 0 = 0; so 0 is represented by the empty set. That should be "0 is...more...
P1.0
31-Aug-13
163 154

#52053: "that is the smallest positive number larger!" doesn't make sense. The last sentence of the paragraph makes the point that this sentence does not. --Mitch Amiano

B6.0
23-Jun-13
168

#58771: in table 3, the cell at row g column d
should be "g" if d = 0

there's also a "1" in (j,b)

P1.0
28-Dec-13
185
#52547: I'm torn between "Typo" and "Technical Error" here "For example, we can create a machine that accepts strings that consist of any string con...more...
P1.0
01-Sep-13
186
#52551: Figure 15 shows state A marked as final. This means that your machine would accept the string "a", which is *not* an element of the set of "...more...
P1.0
01-Sep-13
190
#52548: "all of the different FSMs that you can generate for a particular regular expression will process exactly the same language and will do it i...more...
P1.0
01-Sep-13
190
#52549: In formal terms, let S(r) be the set of strings accepted by the regular expression r. Then if you have a regular expression r and a characte...more...
P1.0
01-Sep-13
192
#52550: A starred regular expression matches zero or one repetitions of a pattern. Zero repetitions is the empty string, so any starred regular expr...more...
P1.0
01-Sep-13
202

#58368: The last state in the list should not contain the minus, since the transition eraseone minus writes space.--Heinz Kabutz

P1.0
27-Dec-13
206

#58778: The link for the Turing Machine written in Haskell points to the website for the book, but the source code zip does not include the TM simulation.--Heinz Kabutz

P1.0
30-Dec-13
238
#52630: The factorial function N! is defined for all natural numbers: for any natural number N, its factorial is the product of all of the integers le...more...
P1.0
13-Sep-13
238
#52633: Please amend my earlier post to say "The factorial function N! is defined for all natural numbers: for any natural number N, its factorial i...more...
P1.0
13-Sep-13
245

#52631: The λ which is the very last character should really be on the next page. --Philip Martel

P1.0
13-Sep-13
246
#52632: The context is usually written as an uppercase letter. If a type context G includes the judgement that x : γ, we’ll write that as G :- x : γ...more...
P1.0
13-Sep-13
248
#52099: Last line substitute 'δ' by 'β' or on the 2nd line of page 249 the other way round: implication isn’t accidental: a function type α → δ is a ...more...
B7.0
30-Jun-13
257
#52634: "And finally, the way that we would write that a program p doesn’t halt for input i is C(p, i) = _." You should probably use the "⊥" you ...more...
P1.0
13-Sep-13