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Standard notations

The following are standard symbols used in this book. Other symbols will be defined as they are introduced, but the below relations and structures will not be defined and are assumed to already be familiar.

aA,bab=0For any element a of A, there exists b such that ab=0
{xP(x)}The set of elements x that satisfy the relation P(x)
Definition
=Equation derivable from given definitions
Is proportional to
, Proper, improper subset, subgroup, etc.
, Union, intersection
, Sum, product
(nk)The binomial coefficient n choose k
, Implies, is true iff (if and only if)
f:MNMapping f from M to N
mnMapping of an element m to an element n
cComplex conjugate of the complex number c
Re(c),Im(c)Real and imaginary parts of the complex number c
|c|Modulus (AKA absolute value) of the complex number c
NThe natural numbers
ZThe integers
Z+The positive integers
ZnThe integers modulo n
RThe real numbers
CThe complex numbers
KA field, typically either the real or complex numbers
HThe quaternions (AKA Hamilton’s quaternions)
OThe octonions (AKA Cayley’s octonions)
RnThe n-dimensional real vector space or Euclidean space
CnThe n-dimensional complex vector space
DnThe dimension n disk (AKA ball), all points of distance (or vectors of length) 1 or less from the origin in Rn
SnThe dimension n sphere, all points of distance (or vectors of length) 1 from the origin in Rn+1
TnThe dimension n torus, the product of n circles
A,AμνMatrix, matrix element of row μ, column ν
AT,A,IMatrix transpose, adjoint, identity
det(A),tr(A)Matrix determinant, trace

An Illustrated Handbook