## Probability distribution

Probability distribution is a term from mathematics. Suppose there are many events with random outcomes. A probability distribution is the theoretical counterpart to the frequency distribution. A frequency distribution simply shows how many times ...

## Product cipher

In cryptography, a product cipher is a popular type of stream ciphers that works by executing in sequence a number of simple transformations such as substitution, permutation, and modular arithmetic. Product ciphers usually consist of iterations ...

## Public-key cryptography

Public-key cryptography, also called asymmetric cryptography, is a communication where people exchange messages that can only be read by one another. In public key cryptography, each user has a pair of cryptographic keys: a public key a private k ...

## Pyramid (geometry)

A pyramid is a three-dimensional shape. It has triangular sides that come together in a point at the top, call the "apex". A pyramid with a square base and four sides is called a square pyramid. A pyramid with a triangular base and is called a te ...

In Euclidean plane geometry, a quadrilateral is a polygon with four edges and four vertices. Sometimes, the term quadrangle is used, while other times, the term tetragon is used. A quadrilateral with vertices A {\displaystyle A}, B {\displaystyle ...

A radian is a unit of measuring angles. It is shown by the symbol "rad" or, less often, c. The radian was once an SI supplementary unit, but was changed to a derived unit in 1995.

## Ramanujan prime

In 1919, Ramanujan published a new proof of Bertrands postulate which had already been proven by Pafnuty Chebyshev. Ramanujans result at the end of the paper was: π x − π x / 2 {\displaystyle \pi x-\pi x/2} ≥ 1, 2, 3, 4, 5. for all x ≥ 2, 11, 17, ...

## Rectangle

In geometry, a rectangle is a shape with four sides and four corners. The corners are all right angles. It follows that the pairs of sides opposite each other must be parallel and of the same length. People make many rectangular things, including ...

## Regular polytope

In mathematics, a regular polytope is the generalisation of the regular polygon. Like other polytopes it may have any natural number of dimensions. For example, a two-dimensional regular polytope is a regular polygon, and a three-dimensional regu ...

## Reuleaux triangle

A Reuleaux triangle is a shape made when three circles cross. It looks like a triangle with round sides and pointed corners. To make one, first draw two dots. Then put a compass on the two dots and draw a circle. Do the same thing again, this tim ...

## Right angle

A right angle is an angle with a measurement of 90 degrees. When two lines cross each other so that all the angles have the same size, the result is four right angles. The top of the letter T is at right angles to the vertical line. Walls of buil ...

## ROT13

ROT13 is a very simple form of encryption cipher. It is a variant of a Caesar cipher. In it, the alphabet is written in two lines, of 13 characters each. Encryption, and decryption is done by simply switching the letters that are below each other ...

## Serpent (cipher)

Serpent is a symmetric key block cipher which was the second finalist in the Advanced Encryption Standard contest after Rijndael. Serpent was designed by Ross Anderson, Eli Biham, and Lars Knudsen. Serpent has a block size of 128 bits and support ...

## Shape

A shape is a geometric figure that can be described with mathematics. One way to classify shapes is to describe a bigger kind of shape that the shape is one of. For example, they can be classified by their different numbers of dimensions. Thus, c ...

## Shared secret

In cryptography, a shared secret is a piece of data only known to the parties involved in a secure communication. The shared secret can be a password, a passphrase, a big number or an array of randomly chosen bytes. The shared secret is either sh ...

## Short (finance)

To short an asset means to bet that the asset will lose value, or that the current price is overvalued. If the asset in question does indeed lose value, the person who shorted it will win the bet, and make a profit. This can be done by borrowing ...

## Sieve of Eratosthenes

The Sieve of Eratosthenes is a simple way to find all the prime numbers up to some number n: Count up from p as 2p, 3p, 4p., up to in steps of p, and cross out each of those numbers. Some numbers will be already crossed out, thats okay. Do not cr ...

## Singular value decomposition

In linear algebra, the singular-value decomposition is a factorization of a real or complex matrix. It is the generalization of the eigendecomposition of a positive semidefinite normal matrix to any matrix via an extension of the polar decomposit ...

## Sphere

A sphere is a shape in space that is like the surface of a ball. Most of the time, the terms ball and sphere are used as the same. But in mathematics, the precise definition only allows points in the 3 dimensional space which are uniformly and sy ...

## Square

A square is a shape with four equal sides and four corners that are all right angles. The diagonals of a square also cross at right angles. The angle between any diagonal and a side of a square is 45 degrees. A square has rotational symmetry of f ...

## Square (cipher)

In cryptography, Square is a block cipher invented by Joan Daemen and Vincent Rijmen. The design was published in 1997. S QUARE is a predecessor to the Rijndael algorithm, which has been adopted in 2001 as the Advanced Encryption Standard by the ...

## Station-to-Station protocol

The Station-to-Station protocol is a cryptographic key agreement scheme based on the classic Diffie-Hellman key exchange that provides mutual key and entity authentication. In addition to protecting the established key from an attacker, the STS p ...

## Substitution box

In cryptography, a S-Box is a basic component of symmetric-key algorithms. In block ciphers, the S-Boxes are used to make the relation between the key and the ciphertext difficult to understand–Shannons property of confusion. The S-Boxes are care ...

## Substitution-permutation network

In cryptography, an SP-network, or substitution-permutation network, is a series of linked mathematical operations used in block cipher algorithms such as AES. These networks consist of S-boxes and P-boxes that transform blocks of input bits into ...

The amount of space a regular tetradecagon takes up is The area of a regular tetradecagon of side length a is given by A = 14 4 a 2 cot ⁡ π 14 = 14 4 a 2 7 + 4 7 cos ⁡ 2 3 arctan ⁡ 3 9 3) ≃ 15.3345 a 2 {\displaystyle {\begin{aligned}A&amp;={\frac ...

## Tetration

Tetration is the hyperoperation which comes after exponentiation. x y {\displaystyle ^{x}{y}} means y exponentiated by itself, times. List of first 4 natural number hyperoperations: Addition a + n = a ″ ⋯ ′ ⏟ n {\displaystyle a+n=a\!\underbrace { ...

## Transcendental number

A real or complex number is called a transcendental number if it cannot be found as a result of an algebraic equation with integer coefficients. a n x n + ⋯ + a 2 x 2 + a 1 x + a 0 = 0 {\displaystyle a_{n}x^{n}+\dots +a_{2}x^{2}+a_{1}x+a_{0}=0} P ...

## Transfinite number

In mathematics, transfinite numbers are numbers that are "infinite" in the sense that they are larger than all finite numbers, but not necessarily absolutely infinite. These numbers can be categorized into two types: transfinite cardinals and tra ...

## Trapezoid

A trapezoid or trapezium is a quadrilateral, which is defined as a shape with four sides, which has one set of parallel sides. In North America, the term "trapezium" is used for what is elsewhere called an irregular quadrilateral.

## Triangle

A triangle is a shape, or a part of two dimensional space. It has three straight sides and three vertices. The three angles of a triangle always add up to 180°. It is the polygon with the least possible number of sides. A triangle with vertices A ...

## Twin prime

A twin prime is a pair of prime numbers, where one prime is two bigger than the other. The smallest pair of twin primes is 3 and 5. Next comes 5 and 7. Then comes 11 and 13, and then 17 and 19.

## Unit vector

A unit vector is any vector that is one unit in length. Unit vectors are often notated the same way as normal vectors, but with a mark over the letter To make a vector into a unit vector, one just needs to divide it by its length: v ^ = v / ‖ v ‖ ...

## Vector space

A vector space is a collection of mathematical objects called vectors, along with some operations you can do on them. Two operations are defined in a vector space: addition of two vectors and multiplication of a vector with a scalar. These operat ...

## Vector subspace

A vector subspace is a vector space that is a subset of another vector space. This means that all the properties of a vector space are satisfied. Let W be a non empty subset of a vector space V, then, W is a vector subspace if and only if the nex ...

## Wilson prime

A Wilson prime is a special kind of prime number. A prime number p is a Wilson prime if p − 1! + 1 p 2 = n {\displaystyle {\frac {\leftp-1\right!+1}{p^{2}}}=n\,\!} where n is a positive integer sometimes called natural number. Wilson primes were ...

## XSL attack

In cryptography, the XSL attack is a method of cryptanalysis for block ciphers. The attack was first published in 2002 by researchers Nicolas Courtois and Josef Pieprzyk. It was claimed that it may break the Advanced Encryption Standard cipher fa ...

## 1 E-10 m

To help compare different orders of magnitude this page lists lengths between −10 m and 10 −9 m. 356.68 pm - width of diamond cell unit cell 175 pm - covalent radius of thulium atom 403 pm - width of lithium fluoride cell 700 pm - width of glucos ...

## 1 E6 m²

To help in showing the sizes of different geographic regions, areas between 1 km² and 10 km² are listed below. 100 hectares a circle of this area has a radius of 564 m 1 square kilometre U.S. spelling: square kilometer, symbol km², is an SI unit ...

## 1 E7 m²

1 E7 m² is a term used to group together areas of similar size. It is used for places that are between 10 km² and 100 km² in area. The term is based from the scientific notation for 1 x 10 7 m². 1.000 hectares 10 km² is equal to 2.471 acres 1 E+7 ...

## 1 E8 m²

1 E8 m² is used for places that are between 100 km² and 1000 km² in area. The term is based from the scientific notation for 1 x 10 8 m². 10.000 hectares approx. 38.6 square miles 1 E+8 m² a square with sides 10 km long 100 km² is equal to approx ...

## 1 E9 m²

1 E9 m² is a term used to group together areas of similar size. It is used for places that are between 1.000 km² and 10.000 km² in area. The term is based from the scientific notation for 1 x 10 9 m². 100.000 hectares 1.000 km² is equal to a circ ...

## Coefficient of thermal expansion

Solids mostly expand in response to heating and contract on cooling. This response to temperature change is expressed as its coefficient of thermal expansion. The coefficient of thermal expansion is used: in area thermal expansion in linear therm ...

## Depth

In math, the distance between the nearest end and farthest end of an object is its depth. For example, Jane measures a box. When she measures the distance between the end of the box closest to her and the end of the box farthest away, Jane measur ...

## Intensity (physics)

In physics, intensity can usually be understood as the strength of something like a beam of light. To figure out the exact intensity of a beam of light or a fire hose spraying water, we need to know how many units of light or water are coming to ...

## Length

Length is a measurement. A ruler can measure length. The length of something is the distance between two ends of the thing. Short means a small length. Long means much length. Short and long are opposites. For two dimensional things, length is us ...

## Moment (physics)

In physics, moment of force is a measure of its tendency to cause a body to rotate about a specific point or axis. In this concept the moment arm, the distance from the axis of rotation, plays an important role. The lever, pulley, gear, and most ...

## Physical constant

In science, a physical constant is a number that does not change. This is different from a mathematical constant, which is not based on a real measurement. There are many physical constants in science. Some famous ones are the speed of light, Pla ...

## Power (physics)

In physics, power is how fast work is done or energy is given from one thing to another. In the SI system of measurement, power is measured in watts. It may take a certain amount of work to make a change in the world, such as lifting a heavy weig ...

## Test

A test is a way of checking something to see if it is true, or false, or if it is edible or not. If something can be tested, or finishes the tests correctly, it is testable. The Concise Oxford English Dictionary defines a test as: "a procedure in ...

## Alfred Binet

Alfred Binet was a French psychologist who invented the first practical IQ test. This is called the Binet–Simon test. In 1905, the French Ministry of Education asked psychologist Alfred Binet to find which students did not learn effectively from ...