page line error 3 -7 b' = (xa+yb) - q(ua+vb) 9 10 "equivalently" instead of "equivently" 16 -15 After "...time intervals." insert "Now signal pulse emissions and receptions can be drawn on the two dimensional sqaure grid in which each point has a time and a velocity component." 19 17 The number 225 should be 232. [The error here comes from the authors' ingnorance of HTML's limitation regarding superscripts: you cannot have two supescripts superimposed, so the intended superscript 25 is replaced by 32.] 19 20 The "p" in "then p divides" should be italicised. 31 12 the sequence 1, 0, 0, 0, 1, 1, 1, 0, 0, ... 31 -16 s-n-2 should be sn-2 31 -9 The statement of the theorem then expresses .... 33 15 "... be a polynomial of degree at least 1." 32 7 Replace "X2+X2+1" by "X2+X+1" 49 -3 Replace "ag" by "ag" 49 -2 Replace "realtion" by "relation" 52 4 Replace "let a be" by "let a be" 62 -12 R instead of R so as to get "is an invertible element of R. Show ..." 82 -18 In Lemma 39: equivalence instead of equvalence. 87 -3 10,000 instead of 10.000 111 -2 Remove the first part of the line up to (and including) "that" 116 14 Replace f by f': "It is easy to see that f' is a morphism." 116 19 Since f'(R) should be f'(R/I). 119 -14 Insert "that" so as to get "... Part 3 is the fact that any two ..." 121 -4 Remove once "the is" so as to get "is the n by n identity matrix." 124 -10 In this exercise (no. 7) we want the rational numbers: Q rather than Q (whatever that is). 125 -13 "Show that S = {0, 1 = alpha0, alpha = alpha1,... alpha14}." 127 -17 Replace "))" by ")" 127 -17 Replace "Cg = Ce" by "Cg(x) = Ce(x)" 128 6 missing ) after second b 134 -10 First X should be replaced by Sym( X). 136 24 After "Proof" insert: By Theorem 9 with f = id and X = Gb1, Gb1b2, Gb1,b2b3, ..., respectively, 151 -2 a instead of a 152 1 a instead of a 153 19 } missing at the end (before ".", of first line Exercise 32). 153 -13 a = i + 21/2. 154 12 a instead of a