Symbols:Abbreviations

Exploratory data analysis is the process of performing preliminary examination of raw data in order to gain insight into their general structure and characteristics, and often identify outliers.

Tools used in this activity include:

For multivariate data or particularly large data sets, kernel density estimation methods can be used.

Having performed an exploratory data analysis, the data engineer may be better placed to make a decision as to what formal statistical methods may then be appropriate.

Electromotive force is a quantity that measures the source of potential energy in an electric circuit.

It is defined as the amount of work per unit electric charge.

essup

Essential supremum.

Let $\struct {X, \Sigma, \mu}$ be a measure space.

Let $f : X \to \R$ be an essentially bounded function:

$\map \mu {\set {x \in X : \size {\map f x} > c} } = 0$

The essential supremum of $\size {\map f x}$ is the supremum of all possible $c$, and is written $\essup \size {\map f x}$.

F

G

GCD or g.c.d.

Greatest common divisor.

Also known as:

highest common factor (hcf or h.c.f.)

greatest common factor (gcf or g.c.f.)

GCF

Greatest common divisor.

Also known as:

greatest common factor (GCD, gcd or g.c.d.)

highest common factor (HCF, hcf or h.c.f.)

GCH

The Generalized Continuum Hypothesis can be abbreviated $\operatorname {GCH}$.

glb

Greatest lower bound.

Another term for infimum.

H

HCF or h.c.f.

Highest common factor.

Also known as greatest common divisor (g.c.d.).

I

ICM

International Congress of Mathematicians.

i.i.d.

Independent and identically distributed.

I.V.P.

L

LCD

The lowest (or least) common denominator.

LHS

Left hand side.

In an equation:

$\text {Expression $1$} = \text {Expression $2$}$

the term $\text {Expression $1$}$ is the left hand side.

LQR

Law of Quadratic Reciprocity.

Let $p$ and $q$ be distinct odd primes.

Then:

$\paren {\dfrac p q} \paren {\dfrac q p} = \paren {-1}^{\dfrac {\paren {p - 1} \paren {q - 1} } 4}$

where $\paren {\dfrac p q}$ and $\paren {\dfrac q p}$ are defined as the Legendre symbol.

An alternative formulation is: $\paren {\dfrac p q} = \begin{cases} \quad \paren {\dfrac q p} & : p \equiv 1 \lor q \equiv 1 \pmod 4 \\ -\paren {\dfrac q p} & : p \equiv q \equiv 3 \pmod 4 \end{cases}$

The fact that these formulations are equivalent is immediate.

This fact is known as the Law of Quadratic Reciprocity, or LQR for short.

lsb or l.s.b.

Least significant bit.

LSC

Lower semicontinuous.

M

MGF or M.G.F.

Moment generating function.

MKS or m.k.s.

MKS is the metre-kilogram-second standard system of units of measurement.

ML

Metalanguage

M.P.

Modus Ponens.

msb or m.s.b.

Most significant bit.

M.S.E. or m.s.e. or MSE

Mean squared error.

M.T.

Modus Tollens.

N

NNF

Negation normal form.

NBG

Von Neumann-Bernays-Gödel set theory.

NP

Nondeterministic polynomial time.

N.P.D. or NPD

North polar distance.

NTM

Nondeterministic Turing machine.

O

ODE

Ordinary differential equation.

OL

Object language

OR

Operations research, also known as operational research.

P

PBC

Proof by contradiction.

PBD

Pairwise balanced design.

PCFI

Principle of Complete Finite Induction (also known as Principle of Complete Induction, or PCI).

PCI

Principle of Complete Induction (also known as Principle of Complete Finite Induction, or PCFI).

PDE

Partial differential equation.

A partial differential equation is a differential equation which has:

one dependent variable

more than one independent variable.

The derivatives occurring in it are therefore partial.

pdf

Probability density function:

Let $\struct {\Omega, \Sigma, \Pr}$ be a probability space.

Let $X$ be an absolutely continuous random variable on $\struct {\Omega, \Sigma, \Pr}$.

Let $P_X$ be the probability distribution of $X$.

Let $\map \BB \R$ be the Borel $\sigma$-algebra of $\R$.

Let $\lambda$ be the Lebesgue measure on $\struct {\R, \map \BB \R}$.

We define the probability density function $f_X$ by:

$\ds f_X = \frac {\d P_X} {\d \lambda}$

where $\dfrac {\d P_X} {\d \lambda}$ denotes the Radon-Nikodym derivative of $P_X$ with respect to $\lambda$.

PERT

Program Evaluation and Review Technique.

PET

Principle of the Excluded Third.

PFI

Principle of Finite Induction.

PGF or p.g.f.

Probability generating function:

Let $X$ be a discrete random variable whose codomain, $\Omega_X$, is a subset of the natural numbers $\N$.

Let $p_X$ be the probability mass function for $X$.

The probability generating function for $X$, denoted $\map {\Pi_X} s$, is the formal power series defined by:

$\ds \map {\Pi_X} s := \sum_{n \mathop = 0}^\infty \map {p_X} n s^n \in \R \sqbrk {\sqbrk s}$

PID or pid

Principal ideal domain:

A principal ideal domain is an integral domain in which every ideal is a principal ideal.

PMF, pmf or p.m.f.

Probability mass function:

Let $\struct {\Omega, \Sigma, \Pr}$ be a probability space.

Let $X: \Omega \to \R$ be a discrete random variable on $\struct {\Omega, \Sigma, \Pr}$.

Then the probability mass function of $X$ is the (real-valued) function $p_X: \R \to \closedint 0 1$ defined as:

$\quad \forall x \in \R: \map {p_X} x = \begin {cases} \map \Pr {\set {\omega \in \Omega: \map X \omega = x} } & : x \in \Omega_X \\ 0 & : x \notin \Omega_X \end {cases}$

where $\Omega_X$ is defined as $\Img X$, the image of $X$.

That is, $\map {p_X} x$ is the probability that the discrete random variable $X$ takes the value $x$.

PMI

Principle of Mathematical Induction.

PNT

Prime Number Theorem.

Poset

Partially Ordered Set.

A partially ordered set is a relational structure $\struct {S, \preceq}$ such that $\preceq$ is a partial ordering.

The partially ordered set $\struct {S, \preceq}$ is said to be partially ordered by $\preceq$.

Q

QED

Quod Erat Demonstrandum

The initials of quod erat demonstrandum, which is Latin for which was to be demonstrated.

These initials were traditionally added to the end of a proof, after the last line which is supposed to contain the statement that was to be proved.

QEF

Quod Erat Faciendum

The initials of quod erat faciendum, which is Latin for which was to be done.

These initials were traditionally added to the end of a geometric construction.

QEI

Quod Erat Inveniendum

The initials of quod erat inveniendum, which is Latin for which was to be found.

These initials were traditionally added after the completion of a calculation (either arithmetic or algebraic).

R

Right Ascension

$\mathrm {RA}$

Used as an abbreviation and to denote the right ascension of a point on the celestial sphere.

Let $P$ be a point on the celestial sphere.

The right ascension of $P$ is the angular distance measured eastwards along the celestial equator from the vernal equinox.

The $\LaTeX$ code for $\mathrm {RA}$ is \mathrm {RA} .

RHS

Right hand side.

In an equation:

$\text {Expression $1$} = \text {Expression $2$}$

the term $\text {Expression $2$}$ is the right hand side.

RHS

Triangle Right-Angle-Hypotenuse-Side Congruence.

Reduced Echelon Form

ref is an abbreviation for reduced echelon form.

rref is an abbreviation for reduced row echelon form.

The matrix $\mathbf A$ is in reduced echelon form if and only if, in addition to being in echelon form, the leading $1$ in any non-zero row is the only non-zero element in the column in which that $1$ occurs.

Such a matrix is called a reduced echelon matrix.

S

SAA

Triangle Side-Angle-Angle Congruence.

SAS

Triangle Side-Angle-Side Congruence.

SAT

SAT problem, otherwise known as a boolean satisfiability problem.

SCF

Simple continued fraction.

s.d.

Standard deviation.

s.e.

Standard error.

SFCF

Simple finite continued fraction.

SHM

Simple harmonic motion.

SI

Le Système International d'Unités (the International System of Units).

SICF

Simple infinite continued fraction.

SSS

Triangle Side-Side-Side Congruence.

SUVAT

A category of problems in elementary applied mathematics and Newtonian physics involving a body $B$ under constant acceleration $\mathbf a$.

They consist of applications of the equations:

Let $B$ be a body under constant acceleration $\mathbf a$.

The following equations apply:

$(1):$ Velocity after Time

$\mathbf v = \mathbf u + \mathbf a t$

$(2):$ Distance after Time

$\mathbf s = \mathbf u t + \dfrac {\mathbf a t^2} 2$

$(3):$ Velocity after Distance

$\mathbf v \cdot \mathbf v = \mathbf u \cdot \mathbf u + 2 \mathbf a \cdot \mathbf s$

where:

$\mathbf u$ is the velocity at time $t = 0$

$\mathbf v$ is the velocity at time $t$

$\mathbf s$ is the displacement of $B$ from its initial position at time $t$

$\cdot$ denotes the dot product.

The term SUVAT arises from the symbols used, $\mathbf s$, $\mathbf u$, $\mathbf v$, $\mathbf a$ and $t$.

T

Toset

Totally Ordered Set.

Let $\struct {S, \preceq}$ be a relational structure.

Then $\struct {S, \preceq}$ is a totally ordered set if and only if $\preceq$ is a total ordering.

U

UE

Universal Elimination (another name for Universal Instantiation: UI).

UF

Ultrafilter Lemma (also UL).

UFD

Unique factorization domain.

UI

Universal Instantiation.

UL

Ultrafilter Lemma (also UF).

URM

Unlimited register machine: an abstraction of a computing device with certain particular characteristics.

V

VNG

Von Neumann-Bernays-Gödel set theory.

W

WFF or wff

Well-formed formula.

WLOG

Without loss of generality.

Suppose there are several cases which need to be investigated.

If the same argument can be used to dispose of two or more of these cases, then it is acceptable in a proof to pick just one of these cases, and announce this fact with the words: Without loss of generality, ..., or just WLOG.

WRT or w.r.t.

(Differentiation) with respect to

(Integration) with respect to

When performing calculus operations, that is differentiation or integration, one needs to announce which variable one is "working with".

Thus the phrase with respect to is (implicitly or explicitly) part of every statement in calculus.