Notation
( \newcommand{\kernel}{\mathrm{null}\,}\)
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 |
---|---|---|
x∈S | x is an element of S | Definition 1.1.2 |
x∉S | x is not an element of S | Definition 1.1.2 |
∅ | the empty set, {} | Definition 1.1.2 |
Z | the set of all integers | Example 1.1.1 |
Q | the set of all rational numbers | Example 1.1.1 |
R | the set of all real numbers | Example 1.1.1 |
C | the set of all complex numbers | Example 1.1.1 |
N | the set of all natural numbers, {0,1,2,…} | Example 1.1.1 |
Z+,Q+,R+ | the set of all positive elements of Z,Q,R | Example 1.1.1 |
Z−,Q−,R− | the set of all negative elements of Z,Q,R | Example 1.1.1 |
Z∗,Q∗,R∗,C∗ | the set of all nonzero elements of Z,Q,R,C | Example 1.1.1 |
Mm×n(S) | the set of all m×n matrices over S | Definition 1.1.3 |
Mn(S) | the set of all n×n matrices over S | Definition 1.1.3 |
A⊆B | A is a subset of the B | Definition 1.1.4 |
A⊊B | A is a proper subset of B | Definition 1.1.4 |
P(A) | the power set of A | Definition 1.1.5 |
A∩B | the intersection of A and B | Definition 1.1.6 |
A∪B | the union of A and B | Definition 1.1.6 |
A−B | the difference of A and B | Definition 1.1.6 |
⋃i∈IAi | {x:x∈Ai for some i∈I} | Definition 1.1.6 |
⋂i∈IAi | {x:x∈Ai for every i∈I} | Definition 1.1.6 |
A×B | the direct product of A and B | Definition 1.1.7 |
f:S→T | function f from S to T | Definition 1.2.1 |
f(U) | the image of a set U under f | Definition 1.2.1 |
f←(V) | the preimage of a set V under f | Definition 1.2.1 |
f∘g | the composition of f with g | Definition 1.2.3 |
1S | the identity function on S | Definition 1.2.3 |
f−1 | the inverse of f | Theorem 1.2.2 |
|S| | the cardinality of S | Definition 1.3.1 |
⟨S,∗⟩ | binary structure | Definition 2.1.1 |
e | the identity element in a binary structure/group | Definition 2.1.4 |
det | the determinant of A | Definition 2.4.1 |
GL(n,\mathbb{R}) | the general linear group of degree n over \mathbb{R} | Definition 2.4.1 |
I_n | the n\times n identity matrix | Theorem 2.4.1 |
e_G | the identity element in a group G | Convention 2.5.1 |
a^{-1} | the inverse of a in a group | Convention 2.5.1 |
-a | the inverse of a in an abelian group | Item |
n\mathbb{Z} | \{nm\,:\,m\in \mathbb{Z}\} | Example 2.6.1 |
a\equiv_n b | a is congruent to b mod n | Definition 2.6.1 |
R_n(a) | the remainder when a is divided by n | Definition 2.6.2 |
+_n | addition modulo n | Definition 2.6.3 |
\mathbb{Z}_n | the cyclic group of order n | Example 2.6.3 |
\mathbb{Z}_n^{\times} | \{a\in \mathbb{Z}_n\,:\,\gcd(a,n)=1\} | Definition 2.6.7 |
F | the set of all functions from \mathbb{R} to \mathbb{R} | Example 2.6.6 |
B | the set of all bijections from \mathbb{R} to \mathbb{R} | Example 2.6.7 |
Z(G) | the center of a group G | Exercise 2.8.9 |
C^1 | the set of all differentiable functions from \mathbb{R} to \mathbb{R} whose derivatives are continuous | Item 6 |
C^0 | the set of all continuous functions from \mathbb{R} to \mathbb{R} | Item 7 |
c_a | conjugation by a | Example 3.2.2 |
G\simeq G' | G is isomorphic to G' | Definition 3.3.1 |
G\not \simeq G' | G is not isomorphic to G' | Definition 3.3.1 |
H\leq G | H is a subgroup of G | Definition 4.1.1 |
H\not \leq G | H is not a subgroup of G | Definition 4.1.1 |
\langle a \rangle | the (cyclic) subgroup generated by a | Definition 5.1.2 |
o(a) | the order of element a | Definition 5.1.2 |
S_A | the set of all permutations on A | Definition 6.1.3 |
S_n | the symmetric group on n letters | Definition 6.2.1 |
A_n | the alternating group on n letters | Definition 6.3.2 |
\lambda_a | left multiplication by a | Definition 6.4.1 |
\rho_a | right multiplication by a | Definition 6.4.1 |
\mapsto | maps to | Paragraph |
D_n | the dihedral group of order 2n | Definition 6.5.1 |
xRy | x is related to y | Definition 7.1.2 |
x\not R y | x is not related to y | Definition 7.1.2 |
[x] | the equivalence class of x | Definition 7.1.4 |
a\sim_L b | a^{-1}b\in H\text{,} where H\leq G is specified | Definition 7.2.1 |
a\sim_R b | ab^{-1}\in H\text{,} where H\leq G is specified | Definition 7.2.1 |
aH, a+H | the left coset of H containing a | Definition 7.2.2 |
Ha, H+a | the right coset of H containing a | Definition 7.2.2 |
\Leftrightarrow | if and only if | Note 7.2 |
H\unlhd G | H is a normal subgorup of G | Definition 7.2.3 |
G/H | the set of all left cosets of H in G | Definition 7.2.4 |
(G:H) | |G/H| | Definition 7.3.1 |
aHb | \{ahb\,:h\in H\} | Definition 8.2.1 |
\text{Ker} \phi | the kernel of \phi | Definition 8.2.3 |
G/N | the factor group G/N\text{,} when N\unlhd G | Definition 8.3.1 |
\Psi | the canonical epimorphism from G to G/N | Definition 8.3.3 |
S^1 | the unit circle \{e^{i\theta} \,:\, \theta\in f\} in the complex plane | Paragraph |