## Logic Primer Errata

### Second Edition

The Fall 2010 printing of Logic Primer fixed all the errors listed below.
Please let Colin Allen know if you disover others.

Here are the known errata in the initial printings of the second edition of Logic Primer by Colin Allen and Michael Hand. Published by The MIT Press 2001

PDF versions of the corrected pages are linked to the page numbers below.

• p. viii - section 4.5 misnumbered in table of contents [there are two 4.4s]
• p. 23 example (b) line (3): assumption set should be '1' (Thanks to Tom Stoneham for notifying us of this one.)
• p. 88 - there are two problems labeled "S107" - second one should be S108
• p. 103 - The definition of ORDERED n-TUPLE has n+1 elements. (Oops! You don't expect logicians to be able to count do you?) It should say "An ORDERED n-TUPLE, <a1, ..., an>, consists of the n objects named by a1, ..., an." (Thanks to Chase Wrenn for notifying us of this one.)
• p. 105 (embarassing!) - the expansion of the conclusion is incorrect, it should be (Raa & Rba) v (Rab & Rbb)
• p. 105 - Ex 4.3.1 ix, conclusion is not well formed. Should be \$x@y(GxyvGyx).
• p. 109 - Ex 4.4 (x): premise should be a universalized conditional - i.e. the second ampersand should be changed to an arrow. The quantifiers on the conclusion should be universal x, y and z ('z' is currently unbound). (Thanks to Tom Stoneham.)
• p. 116 - answer to S3 line 5 should be as follows:
1,3 (5) ~Q .1,4->E [not 1,3 ->E as in book]
(Thanks to Casey MacDonald for spotting this)
• p. 117 - answer to S7 line 4 should be:
2 (4) R v ~P -> P v Q 2 <->E [not a biconditional as in book]
• p. 155
- answer to ii. has serious formatting problems. The five columns should be under P, Q, ~, &, and v respectively.
- answer to v., the first truth value under the wedge in 'R v ~P' should be T [and not F as in the book]
• p. 158
- answer to xiv., line 7 should be 3, 6 RAA [not 2, 6 RAA as in the book]
• p. 166 - #44 is 3-way ambiguous between
(1) Everyone had an audience. (The given answer.)
(2) There is a person who heard from everyone. \$x(Px & @y(Py->\$zSyzx))
(3) There is a message conveyed from each to each. \$x@y(Py->\$z(Pz & Syxz))
(Thanks to Torin Alter.)
• p. 172 - S105, line 10: The rule cited should be "&Comm" not simply "Comm" (Thanks to Joshua Cutbirth for spotting this one.)
• p. 175 - S130, line 9: The annotation should be "6,8 MTT", not "6,8 →E" (Thanks to Patrick O'Sullivan for this one.)
• Note -- there used to be mention on this page of an error at p.184, but this itself seems to have been an error. The correct expansion of the conclusion of 4.3.1 iii, \$x@yFxy, is (Faa & Fab) v (Fba & Fbb). The bad news is that the incorrect expansion is in the 2010 printing, so here's a link to the original correct page: 184. (Thanks to Matthew Pendlington for pointing this out.)
Thanks to students at TAMU for noticing many of these.

### First Edition

Here are the known errata in the first, second and third printings of Logic Primer by Colin Allen and Michael Hand. Published by The MIT Press 1992 ISBN 0-262-51065-0.

Q How do I know which printing I have?
A Look at the copyright page (unnumbered page iv). If it says "Second printing, 1994" or "Third printing, 1996" at the top, then you do not have the first printing. The second and third printings are identical except for the copyright page.

Please report any additional errors by email to Colin Allen

```
Page	Description						STATUS
---------------------------------------------------------------------------
29	Chapter 1 Example (b) line 4 subsitutions should be	2
(P/T; Q/~S; R/PvR)
30	T4 missing asterisk (answer in back)			2
T6 should be no asterisk (no answer in back)		2
58	Chapter 3 Exercise 3.3 Instructions should		1
say "expressions" not "sentences".
59	Chapter 3 comment on universalization should
say replace all occurences of the *name* with
a variable alpha.                                       2
75	T55: RHS should be ~(UxFx -> P)				1
85	Chapter 4 Second ordered pair is reversed		1
86   	Chapter 4 Should be EyFay & EyFby (not ExFby)		1
87	Chapter 4 Expansion of conclusion should be		2
(Raa & Rba) v (Rab & Rbb)
87   	Chapter 4 Exercise 4.4 ix is valid.			1
Third premise should be ExyFxy <-> Exy(Gyx & ~Gxy)
91	Chapter 4 Exercise 4.6 contains duplicates		1
93	Answers 1.2(a)xiii should be & not v			2
99	Answers S18(a) Line 8 annotation should be 4,7 &I	1
104	Answers S43(b) Line 12 is superfluous (not an error)	2
108	Answers T8(i)  Line 30 annotation should be 28 <->E	2
110	Answers T10(i) Line 12 assump 1 should be discharged	2
115	Answers T17(ii) Line 12 should be PvR			2
Line 15 should contain R<->S not S<->S	2
120	Answers T27(ii) Line 1 should begin ~(((		2
Line 12 missing ) at end		2
122	Answers T30(i)	Line 61 should be 46,60RAA(46)		2
Line 62 should be 61->I(39)		2
Line 63 should be 38,62<->I		2
125	Answers T31(i) Line 63 should be 62vI			2
138 	Answers 2.1ix 7th row of PvR should be T		1
139  	Answers 2.2iv Line 4 annotation should be 1,3 ->E	1
149	Answers 3.5 28 Missing right parenthesis on alt answer	2
150	Answers S98 Line 10 extra right parenthesis at end	2
151	Answers 3.6 S78 Line (5) is superfluous            	2
156	Answers S96   Assump set lines 18 and 19 should be 18	2
156	Answers S98   Last line should read			2
@z(Dx -> (@y(Fy -> Gy) -> Gz))
157	Answers S100  Line 15, rule should be @I		2
Line 22 should be <->I                    2
161	Answers T40 First two lines are A [for ->I]		2
163  	Answers T59 needs last line				1
165  	Answers 4.3vii Expansion of conclusion is incorrect	1
166	Answers 4.4iv Expansion of second premise needs ~Faa	2

STATUS codes:
1	First printing only
2	All printings

```

Last updated May 23, 2020