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Appendix C Notation

The following table defines the notation used in this book. Page numbers or references refer to the first appearance of each symbol.
Symbol Description Location
aA a is in the set A Paragraph
N the natural numbers Paragraph
Z the integers Paragraph
Q the rational numbers Paragraph
R the real numbers Paragraph
C the complex numbers Paragraph
AB A is a subset of B Paragraph
the empty set Paragraph
AB the union of sets A and B Paragraph
AB the intersection of sets A and B Paragraph
A complement of the set A Paragraph
AB difference between sets A and B Paragraph
A×B Cartesian product of sets A and B Paragraph
An A××A (n times) Paragraph
id identity mapping Paragraph
f1 inverse of the function f Paragraph
ab(modn) a is congruent to b modulo n Example 1.30
n! n factorial Example 2.4
(nk) binomial coefficient n!/(k!(nk)!) Example 2.4
ab a divides b Paragraph
gcd(a,b) greatest common divisor of a and b Paragraph
P(X) power set of X Exercise 2.4.12
lcm(m,n) the least common multiple of m and n Exercise 2.4.23
Zn the integers modulo n Paragraph
U(n) group of units in Zn Example 3.11
Mn(R) the n×n matrices with entries in R Example 3.14
detA the determinant of A Example 3.14
GLn(R) the general linear group Example 3.14
Q8 the group of quaternions Example 3.15
C the multiplicative group of complex numbers Example 3.16
|G| the order of a group Paragraph
R the multiplicative group of real numbers Example 3.24
Q the multiplicative group of rational numbers Example 3.24
SLn(R) the special linear group Example 3.26
Z(G) the center of a group Exercise 3.5.48
a cyclic group generated by a Theorem 4.3
|a| the order of an element a Paragraph
cisθ cosθ+isinθ Paragraph
T the circle group Paragraph
Sn the symmetric group on n letters Paragraph
(a1,a2,,ak) cycle of length k Paragraph
An the alternating group on n letters Paragraph
Dn the dihedral group Paragraph
[G:H] index of a subgroup H in a group G Paragraph
LH the set of left cosets of a subgroup H in a group G Theorem 6.8
RH the set of right cosets of a subgroup H in a group G Theorem 6.8
ab a does not divide b Theorem 6.19
d(x,y) Hamming distance between x and y Paragraph
dmin the minimum distance of a code Paragraph
w(x) the weight of x Paragraph
Mm×n(Z2) the set of m×n matrices with entries in Z2 Paragraph
Null(H) null space of a matrix H Paragraph
δij Kronecker delta Lemma 8.27
GH G is isomorphic to a group H Paragraph
Aut(G) automorphism group of a group G Exercise 9.4.37
ig ig(x)=gxg1 Exercise 9.4.41
Inn(G) inner automorphism group of a group G Exercise 9.4.41
ρg right regular representation Exercise 9.4.44
G/N factor group of G mod N Paragraph
G commutator subgroup of G Exercise 10.4.14
kerϕ kernel of ϕ Paragraph
(aij) matrix Paragraph
O(n) orthogonal group Paragraph
x length of a vector x Paragraph
SO(n) special orthogonal group Paragraph
E(n) Euclidean group Paragraph
Ox orbit of x Paragraph
Xg fixed point set of g Paragraph
Gx isotropy subgroup of x Paragraph
N(H) normalizer of s subgroup H Paragraph
H the ring of quaternions Example 16.7
Z[i] the Gaussian integers Example 16.12
charR characteristic of a ring R Paragraph
Z(p) ring of integers localized at p Exercise 16.7.33
degf(x) degree of a polynomial Paragraph
R[x] ring of polynomials over a ring R Paragraph
R[x1,x2,,xn] ring of polynomials in n indeterminants Paragraph
ϕα evaluation homomorphism at α Theorem 17.5
Q(x) field of rational functions over Q Example 18.5
ν(a) Euclidean valuation of a Paragraph
F(x) field of rational functions in x Item 18.4.7.a
F(x1,,xn) field of rational functions in x1,,xn Item 18.4.7.b
ab a is less than b Paragraph
ab join of a and b Paragraph
ab meet of a and b Paragraph
I largest element in a lattice Paragraph
O smallest element in a lattice Paragraph
a complement of a in a lattice Paragraph
dimV dimension of a vector space V Paragraph
UV direct sum of vector spaces U and V Item 20.5.17.b
Hom(V,W) set of all linear transformations from U into V Item 20.5.18.a
V dual of a vector space V Item 20.5.18.b
F(α1,,αn) smallest field containing F and α1,,αn Paragraph
[E:F] dimension of a field extension of E over F Paragraph
GF(pn) Galois field of order pn Paragraph
F multiplicative group of a field F Paragraph
G(E/F) Galois group of E over F Paragraph
F{σi} field fixed by the automorphism σi Proposition 23.14
FG field fixed by the automorphism group G Corollary 23.15
Δ2 discriminant of a polynomial Exercise 23.5.22