## A

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 7 words.

The number 10 in hexadecimal notation.

## a-

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 19 words.

Prefix meaning ‘not’. For example, an asymmetric figure is one which possesses no symmetry, which is not symmetrical.

## abacus

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 26 words.

A counting device consisting of rods on which beads can be moved so as to represent numbers.

## Abel, Niels Henrik (1802–29)

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 94 words.

who, at the age of 19, proved that the general equation of degree greater than 4 cannot be solved algebraically. In other words, there can be no formula for the roots of such an equation...

## Abel summation

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 40 words.

A method of computing the sum of a possibly *divergent series of *complex numbers as the limit, as ...

## Abel’s Limit Theorem

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 30 words.

For a *convergent series {*a _{k}
*}, the limit assigned by the Abel summation method exists and is equal to the sum of the series....

## Abel’s partial summation formula

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 25 words.

For two arbitrary sequences and with , the result that . This has some similarities with the formula for *integration by parts....

## Abel’s test

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 49 words.

A test for the convergence of an infinite series which states that if ∑*a*
_{
n
} is a convergent sequence, and {...

## abelian group

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 41 words.

Suppose that *G* is a *group with the operation ￮. Then *G* is abelian if the operation ￮ is commutative; that is, if, for all elements ...

## above

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 67 words.

Greater than. The limit of a function at *a* from above is the limit of *f*(*x*) as ...

## abscissa

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 12 words.

The *x*-coordinate in a Cartesian coordinate system in the plane.

## absolute address

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 96 words.

In spreadsheets a formula which is to appear in a number of cells may wish to use the contents of another cell or cells. Since the relative position of those cells will be different each...

## absolute error

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 4 words.

## absolute frequency

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 37 words.

The number of occurrences of an event. For example, if a die is rolled 20 times and 4 sixes are observed the absolute frequency of sixes is 4 and the ...

## absolute measure of dispersion

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 8 words.

## absolute value

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 41 words.

For any real number the absolute value (also called the *modulus) of denoted by is itself if and ...

## absolutely continuous function

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 62 words.

A stronger condition than *continuous function or *uniformly continuous function. It says that a function *f* on an interval ...

## absolutely convergent series

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 31 words.

A series is said to be absolutely convergent if is *convergent. For example, if then the series is convergent but not absolutely convergent, whereas ...

## absolutely summable

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 5 words.

## absorbing set

in** The Concise Oxford Dictionary of Mathematics**

January 2014; p ublished online September 2014 .

Reference Entry. Subjects: Pure Mathematics. 81 words.

A subset *S* of a *vector space *X* is an absorbing set if for any point *x* in *X...*