Table of Contents
264 relations: Abundant number, AD 2, Aegean numerals, Aliquot sum, Andrew Wiles, Antipodal point, Apeirogon, Arabic numerals, Armenian numerals, Atomic number, Babylonian cuneiform numerals, Bani (letter), Bengali numerals, Bernoulli number, Binary number, Boundary (topology), Brahmic scripts, Cambridge University Press, Cantor set, Cantor space, Cantor's theorem, Cardinal number, Category theory, Chaos theory, Chinese numerals, Circle, Circumcircle, Closed set, Composite number, Computer, Computer science, Constructible polygon, Continued fraction, Counting rods, Critical exponent of a word, Culture, Cunningham chain, De Gruyter, Decimal, Deficient number, Devanagari, Digon, Dihedron, Discrete Mathematics & Theoretical Computer Science, Discrete two-point space, Division (mathematics), Divisor, Divisor function, DNA, Dualism in cosmology, ... Expand index (214 more) »
- 2 (number)
Abundant number
In number theory, an abundant number or excessive number is a positive integer for which the sum of its proper divisors is greater than the number.
AD 2
AD 2 (II) or 2 AD was a common year starting on Sunday or Monday (the link will display the full calendar) of the Julian calendar (sources differ, see leap year error for further information) and a common year starting on Sunday of the proleptic Julian calendar.
See 2 and AD 2
Aegean numerals
Aegean numbers was an additive sign-value numeral system used by the Minoan and Mycenaean civilizations.
Aliquot sum
In number theory, the aliquot sum of a positive integer is the sum of all proper divisors of, that is, all divisors of other than itself.
Andrew Wiles
Sir Andrew John Wiles (born 11 April 1953) is an English mathematician and a Royal Society Research Professor at the University of Oxford, specialising in number theory.
Antipodal point
In mathematics, two points of a sphere (or n-sphere, including a circle) are called antipodal or diametrically opposite if they are the endpoints of a diameter, a straight line segment between two points on a sphere and passing through its center.
Apeirogon
In geometry, an apeirogon or infinite polygon is a polygon with an infinite number of sides.
See 2 and Apeirogon
Arabic numerals
The ten Arabic numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 are the most commonly used symbols for writing numbers.
Armenian numerals
Armenian numerals form a historic numeral system created using the majuscules (uppercase letters) of the Armenian alphabet.
Atomic number
The atomic number or nuclear charge number (symbol Z) of a chemical element is the charge number of an atomic nucleus.
Babylonian cuneiform numerals
Babylonian cuneiform numerals, also used in Assyria and Chaldea, were written in cuneiform, using a wedge-tipped reed stylus to print a mark on a soft clay tablet which would be exposed in the sun to harden to create a permanent record.
See 2 and Babylonian cuneiform numerals
Bani (letter)
Bani (asomtavruli, nuskhuri, mkhedruli ბ, mtavruli Ბ) is the 2nd letter of the three Georgian scripts.
Bengali numerals
Bengali–Assamese numerals (xoiŋkha, sôṅkhya, ꯃꯁꯤꯡ|mashing) are the units of the numeral system, originating from the Indian subcontinent, used officially in Assamese, Bengali, and Manipuri, 3 of the 22 official languages of the Indian Republic, as well as traditionally in Bishnupriya, Chakma and Hajong languages.
Bernoulli number
In mathematics, the Bernoulli numbers are a sequence of rational numbers which occur frequently in analysis.
Binary number
A binary number is a number expressed in the base-2 numeral system or binary numeral system, a method for representing numbers that uses only two symbols for the natural numbers: typically "0" (zero) and "1" (one).
Boundary (topology)
In topology and mathematics in general, the boundary of a subset of a topological space is the set of points in the closure of not belonging to the interior of.
Brahmic scripts
The Brahmic scripts, also known as Indic scripts, are a family of abugida writing systems.
Cambridge University Press
Cambridge University Press is the university press of the University of Cambridge.
See 2 and Cambridge University Press
Cantor set
In mathematics, the Cantor set is a set of points lying on a single line segment that has a number of unintuitive properties.
See 2 and Cantor set
Cantor space
In mathematics, a Cantor space, named for Georg Cantor, is a topological abstraction of the classical Cantor set: a topological space is a Cantor space if it is homeomorphic to the Cantor set.
Cantor's theorem
In mathematical set theory, Cantor's theorem is a fundamental result which states that, for any set A, the set of all subsets of A, known as the power set of A, has a strictly greater cardinality than A itself.
Cardinal number
In mathematics, a cardinal number, or cardinal for short, is what is commonly called the number of elements of a set.
Category theory
Category theory is a general theory of mathematical structures and their relations.
Chaos theory
Chaos theory is an interdisciplinary area of scientific study and branch of mathematics.
Chinese numerals
Chinese numerals are words and characters used to denote numbers in written Chinese.
Circle
A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre.
See 2 and Circle
Circumcircle
In geometry, the circumscribed circle or circumcircle of a triangle is a circle that passes through all three vertices.
Closed set
In geometry, topology, and related branches of mathematics, a closed set is a set whose complement is an open set.
See 2 and Closed set
Composite number
A composite number is a positive integer that can be formed by multiplying two smaller positive integers.
Computer
A computer is a machine that can be programmed to automatically carry out sequences of arithmetic or logical operations (computation).
See 2 and Computer
Computer science
Computer science is the study of computation, information, and automation.
Constructible polygon
In mathematics, a constructible polygon is a regular polygon that can be constructed with compass and straightedge.
See 2 and Constructible polygon
Continued fraction
In mathematics, a continued fraction is an expression obtained through an iterative process of representing a number as the sum of its integer part and the reciprocal of another number, then writing this other number as the sum of its integer part and another reciprocal, and so on.
Counting rods
Counting rods (筭) are small bars, typically 3–14 cm (1" to 6") long, that were used by mathematicians for calculation in ancient East Asia.
Critical exponent of a word
In mathematics and computer science, the critical exponent of a finite or infinite sequence of symbols over a finite alphabet describes the largest number of times a contiguous subsequence can be repeated.
See 2 and Critical exponent of a word
Culture
Culture is a concept that encompasses the social behavior, institutions, and norms found in human societies, as well as the knowledge, beliefs, arts, laws, customs, capabilities, and habits of the individuals in these groups.
See 2 and Culture
Cunningham chain
In mathematics, a Cunningham chain is a certain sequence of prime numbers.
De Gruyter
Walter de Gruyter GmbH, known as De Gruyter, is a German scholarly publishing house specializing in academic literature.
See 2 and De Gruyter
Decimal
The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers.
See 2 and Decimal
Deficient number
In number theory, a deficient number or defective number is a positive integer for which the sum of divisors of is less than.
Devanagari
Devanagari (देवनागरी) is an Indic script used in the northern Indian subcontinent.
See 2 and Devanagari
Digon
In geometry, a bigon, digon, or a 2-gon, is a polygon with two sides (edges) and two vertices. 2 and digon are 2 (number).
See 2 and Digon
Dihedron
A dihedron is a type of polyhedron, made of two polygon faces which share the same set of n edges.
See 2 and Dihedron
Discrete Mathematics & Theoretical Computer Science
Discrete Mathematics & Theoretical Computer Science is a peer-reviewed open access scientific journal covering discrete mathematics and theoretical computer science.
See 2 and Discrete Mathematics & Theoretical Computer Science
Discrete two-point space
In topology, a branch of mathematics, a discrete two-point space is the simplest example of a totally disconnected discrete space.
See 2 and Discrete two-point space
Division (mathematics)
Division is one of the four basic operations of arithmetic.
See 2 and Division (mathematics)
Divisor
In mathematics, a divisor of an integer n, also called a factor of n, is an integer m that may be multiplied by some integer to produce n. In this case, one also says that n is a multiple of m. An integer n is divisible or evenly divisible by another integer m if m is a divisor of n; this implies dividing n by m leaves no remainder.
See 2 and Divisor
Divisor function
In mathematics, and specifically in number theory, a divisor function is an arithmetic function related to the divisors of an integer.
DNA
Deoxyribonucleic acid (DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix.
See 2 and DNA
Dualism in cosmology
Dualism in cosmology or dualistic cosmology is the moral or spiritual belief that two fundamental concepts exist, which often oppose each other.
See 2 and Dualism in cosmology
E (mathematical constant)
The number is a mathematical constant approximately equal to 2.71828 that can be characterized in many ways.
See 2 and E (mathematical constant)
Eastern Arabic numerals
The Eastern Arabic numerals, also called Indo-Arabic numerals, are the symbols used to represent numerical digits in conjunction with the Arabic alphabet in the countries of the Mashriq (the east of the Arab world), the Arabian Peninsula, and its variant in other countries that use the Persian numerals on the Iranian plateau and in Asia.
See 2 and Eastern Arabic numerals
Edge (geometry)
In geometry, an edge is a particular type of line segment joining two vertices in a polygon, polyhedron, or higher-dimensional polytope.
Egyptian numerals
The system of ancient Egyptian numerals was used in Ancient Egypt from around 3000 BC until the early first millennium AD.
Element (mathematics)
In mathematics, an element (or member) of a set is any one of the distinct objects that belong to that set.
See 2 and Element (mathematics)
Empty set
In mathematics, the empty set is the unique set having no elements; its size or cardinality (count of elements in a set) is zero.
See 2 and Empty set
English determiners
English determiners (also known as determinatives) are words – such as the, a, each, some, which, this, and numerals such as six – that are most commonly used with nouns to specify their referents.
English nouns
English nouns form the largest category of words in English, both in the number of different words and how often they are used in typical texts.
Equilateral triangle
In geometry, an equilateral triangle is a triangle in which all three sides have the same length.
See 2 and Equilateral triangle
Euclidean geometry
Euclidean geometry is a mathematical system attributed to ancient Greek mathematician Euclid, which he described in his textbook on geometry, Elements.
Euclidean plane
In mathematics, a Euclidean plane is a Euclidean space of dimension two, denoted \textbf^2 or \mathbb^2. 2 and Euclidean plane are 2 (number).
Euclidean space
Euclidean space is the fundamental space of geometry, intended to represent physical space.
Euler characteristic
In mathematics, and more specifically in algebraic topology and polyhedral combinatorics, the Euler characteristic (or Euler number, or Euler–Poincaré characteristic) is a topological invariant, a number that describes a topological space's shape or structure regardless of the way it is bent.
See 2 and Euler characteristic
Euler's theorem in geometry
In geometry, Euler's theorem states that the distance d between the circumcenter and incenter of a triangle is given by d^2.
See 2 and Euler's theorem in geometry
Exponentiation
In mathematics, exponentiation is an operation involving two numbers: the base and the exponent or power.
Face (geometry)
In solid geometry, a face is a flat surface (a planar region) that forms part of the boundary of a solid object; a three-dimensional solid bounded exclusively by faces is a polyhedron.
Fermat number
In mathematics, a Fermat number, named after Pierre de Fermat, the first known to have studied them, is a positive integer of the form:F_.
Field (mathematics)
In mathematics, a field is a set on which addition, subtraction, multiplication, and division are defined and behave as the corresponding operations on rational and real numbers.
Fixed point (mathematics)
In mathematics, a fixed point (sometimes shortened to fixpoint), also known as an invariant point, is a value that does not change under a given transformation.
See 2 and Fixed point (mathematics)
Florida Atlantic University
Florida Atlantic University (Florida Atlantic or FAU) is a public research university with its main campus in Boca Raton, Florida and satellite campuses in Dania Beach, Davie, Fort Lauderdale, Jupiter, and Fort Pierce.
See 2 and Florida Atlantic University
Forum Geometricorum
Forum Geometricorum: A Journal on Classical Euclidean Geometry is a peer-reviewed open-access academic journal that specializes in mathematical research papers on Euclidean geometry.
Function (mathematics)
In mathematics, a function from a set to a set assigns to each element of exactly one element of.
See 2 and Function (mathematics)
Geʽez script
Geʽez (Gəʽəz) is a script used as an abugida (alphasyllabary) for several Afro-Asiatic and Nilo-Saharan languages of Ethiopia and Eritrea.
Generalized continued fraction
In complex analysis, a branch of mathematics, a generalized continued fraction is a generalization of regular continued fractions in canonical form, in which the partial numerators and partial denominators can assume arbitrary complex values.
See 2 and Generalized continued fraction
Genus (mathematics)
In mathematics, genus (genera) has a few different, but closely related, meanings.
Genus g surface
In mathematics, a genus g surface (also known as a g-torus or g-holed torus) is a surface formed by the connected sum of g distinct tori: the interior of a disk is removed from each of g distinct tori and the boundaries of the g many disks are identified (glued together), forming a g-torus.
Georgian numerals
The Georgian numerals are the system of number names used in Georgian, a language spoken in the country of Georgia.
Grammatical gender
In linguistics, a grammatical gender system is a specific form of a noun class system, where nouns are assigned to gender categories that are often not related to the real-world qualities of the entities denoted by those nouns.
Grammatical number
In linguistics, grammatical number is a feature of nouns, pronouns, adjectives and verb agreement that expresses count distinctions (such as "one", "two" or "three or more").
Greek numerals
Greek numerals, also known as Ionic, Ionian, Milesian, or Alexandrian numerals, are a system of writing numbers using the letters of the Greek alphabet.
Gupta script
The Gupta script (sometimes referred to as Gupta Brahmi script or Late Brahmi script)Sharma, Ram.
Hanja
Hanja, alternatively known as Hancha, are Chinese characters used to write the Korean language.
See 2 and Hanja
Harmonic divisor number
In mathematics, a harmonic divisor number or Ore number is a positive integer whose divisors have a harmonic mean that is an integer.
See 2 and Harmonic divisor number
Harmonic mean
In mathematics, the harmonic mean is one of several kinds of average, and in particular, one of the Pythagorean means.
Harshad number
In mathematics, a harshad number (or Niven number) in a given number base is an integer that is divisible by the sum of its digits when written in that base.
Hebrew numerals
The system of Hebrew numerals is a quasi-decimal alphabetic numeral system using the letters of the Hebrew alphabet.
Helium
Helium (from lit) is a chemical element; it has symbol He and atomic number 2.
See 2 and Helium
Hexagon
In geometry, a hexagon (from Greek ἕξ, hex, meaning "six", and γωνία, gonía, meaning "corner, angle") is a six-sided polygon.
See 2 and Hexagon
Highly composite number
A highly composite number is a positive integer that has more divisors than any smaller positive integer.
See 2 and Highly composite number
Hindustani numerals
Like many Indo-Aryan languages, Hindustani (Hindi-Urdu) has a decimal numeral system that is contracted to the extent that nearly every number 1–99 is irregular, and needs to be memorized as a separate numeral.
Homeomorphism
In mathematics and more specifically in topology, a homeomorphism (from Greek roots meaning "similar shape", named by Henri Poincaré), also called topological isomorphism, or bicontinuous function, is a bijective and continuous function between topological spaces that has a continuous inverse function.
Hyperoperation
In mathematics, the hyperoperation sequence is an infinite sequence of arithmetic operations (called hyperoperations in this context) that starts with a unary operation (the successor function with n.
II
II is the Roman numeral for 2.
See 2 and II
Incircle and excircles
In geometry, the incircle or inscribed circle of a triangle is the largest circle that can be contained in the triangle; it touches (is tangent to) the three sides.
See 2 and Incircle and excircles
Indeterminate form
In calculus, it is usually possible to compute the limit of the sum, difference, product, quotient or power of two functions by taking the corresponding combination of the separate limits of each respective function.
Infinity
Infinity is something which is boundless, endless, or larger than any natural number.
See 2 and Infinity
Integer
An integer is the number zero (0), a positive natural number (1, 2, 3,...), or the negation of a positive natural number (−1, −2, −3,...). The negations or additive inverses of the positive natural numbers are referred to as negative integers. 2 and integer are integers.
See 2 and Integer
International Journal of Foundations of Computer Science
The International Journal of Foundations of Computer Science is a computer science journal published by World Scientific.
See 2 and International Journal of Foundations of Computer Science
Iteration
Iteration is the repetition of a process in order to generate a (possibly unbounded) sequence of outcomes.
See 2 and Iteration
Japanese writing system
The modern Japanese writing system uses a combination of logographic kanji, which are adopted Chinese characters, and syllabic kana.
See 2 and Japanese writing system
John Horton Conway
John Horton Conway (26 December 1937 – 11 April 2020) was an English mathematician active in the theory of finite groups, knot theory, number theory, combinatorial game theory and coding theory.
Joseph H. Silverman
Joseph Hillel Silverman (born March 27, 1955, New York City) is a professor of mathematics at Brown University working in arithmetic geometry, arithmetic dynamics, and cryptography.
Kannada script
The Kannada script (IAST: Kannaḍa lipi; obsolete: Kanarese or Canarese script in English) is an abugida of the Brahmic family, used to write Kannada, one of the Dravidian languages of South India especially in the state of Karnataka.
Khmer numerals
Khmer numerals are the numerals used in the Khmer language.
Knuth's up-arrow notation
In mathematics, Knuth's up-arrow notation is a method of notation for very large integers, introduced by Donald Knuth in 1976.
See 2 and Knuth's up-arrow notation
Labialization
Labialization is a secondary articulatory feature of sounds in some languages.
Limit inferior and limit superior
In mathematics, the limit inferior and limit superior of a sequence can be thought of as limiting (that is, eventual and extreme) bounds on the sequence.
See 2 and Limit inferior and limit superior
Line (geometry)
In geometry, a straight line, usually abbreviated line, is an infinitely long object with no width, depth, or curvature, an idealization of such physical objects as a straightedge, a taut string, or a ray of light.
Logistic map
The logistic map is a polynomial mapping (equivalently, recurrence relation) of degree 2, often referred to as an archetypal example of how complex, chaotic behaviour can arise from very simple nonlinear dynamical equations.
Look-and-say sequence
In mathematics, the look-and-say sequence is the sequence of integers beginning as follows: To generate a member of the sequence from the previous member, read off the digits of the previous member, counting the number of digits in groups of the same digit.
See 2 and Look-and-say sequence
Magic constant
The magic constant or magic sum of a magic square is the sum of numbers in any row, column, or diagonal of the magic square.
Magic number (physics)
In nuclear physics, a magic number is a number of nucleons (either protons or neutrons, separately) such that they are arranged into complete shells within the atomic nucleus.
See 2 and Magic number (physics)
Magic square
In mathematics, especially historical and recreational mathematics, a square array of numbers, usually positive integers, is called a magic square if the sums of the numbers in each row, each column, and both main diagonals are the same.
Magic star
An n-pointed magic star is a star polygon with Schläfli symbol in which numbers are placed at each of the n vertices and n intersections, such that the four numbers on each line sum to the same magic constant.
See 2 and Magic star
Malayalam numerals
Malayalam numerals are the numeral system of the Malayalam script used by Malayalam in Kerala.
Map (mathematics)
In mathematics, a map or mapping is a function in its general sense.
Mathematical Association of America
The Mathematical Association of America (MAA) is a professional society that focuses on mathematics accessible at the undergraduate level.
See 2 and Mathematical Association of America
Maya numerals
The Mayan numeral system was the system to represent numbers and calendar dates in the Maya civilization.
Mersenne prime
In mathematics, a Mersenne prime is a prime number that is one less than a power of two.
Mertens function
In number theory, the Mertens function is defined for all positive integers n as where \mu(k) is the Möbius function.
Morse code
Morse code is a telecommunications method which encodes text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs.
See 2 and Morse code
Multiple (mathematics)
In mathematics, a multiple is the product of any quantity and an integer. 2 and multiple (mathematics) are integers.
See 2 and Multiple (mathematics)
Multiplication
Multiplication (often denoted by the cross symbol, by the mid-line dot operator, by juxtaposition, or, on computers, by an asterisk) is one of the four elementary mathematical operations of arithmetic, with the other ones being addition, subtraction, and division.
Multiplicative inverse
In mathematics, a multiplicative inverse or reciprocal for a number x, denoted by 1/x or x−1, is a number which when multiplied by x yields the multiplicative identity, 1.
See 2 and Multiplicative inverse
Natural number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, etc., possibly excluding 0. 2 and natural number are integers.
Necessity and sufficiency
In logic and mathematics, necessity and sufficiency are terms used to describe a conditional or implicational relationship between two statements.
See 2 and Necessity and sufficiency
Nucleic acid double helix
In molecular biology, the term double helix refers to the structure formed by double-stranded molecules of nucleic acids such as DNA.
See 2 and Nucleic acid double helix
Null set
In mathematical analysis, a null set is a Lebesgue measurable set of real numbers that has measure zero.
See 2 and Null set
Number
A number is a mathematical object used to count, measure, and label.
See 2 and Number
Number line
In elementary mathematics, a number line is a picture of a straight line that serves as spatial representation of numbers, usually graduated like a ruler with a particular origin point representing the number zero and evenly spaced marks in either direction representing integers, imagined to extend infinitely.
Number Two
Number Two, No.
See 2 and Number Two
Numeral (linguistics)
In linguistics, a numeral in the broadest sense is a word or phrase that describes a numerical quantity.
See 2 and Numeral (linguistics)
Numeral system
A numeral system is a writing system for expressing numbers; that is, a mathematical notation for representing numbers of a given set, using digits or other symbols in a consistent manner.
Numerical digit
A numerical digit (often shortened to just digit) or numeral is a single symbol used alone (such as "1") or in combinations (such as "15"), to represent numbers in a positional numeral system.
Octagon
In geometry, an octagon is an eight-sided polygon or 8-gon.
See 2 and Octagon
Old English
Old English (Englisċ or Ænglisc), or Anglo-Saxon, was the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages.
One half
One half is the irreducible fraction resulting from dividing one (1) by two (2), or the fraction resulting from dividing any number by its double.
See 2 and One half
Order-2 apeirogonal tiling
In geometry, an order-2 apeirogonal tiling, apeirogonal dihedron, or infinite dihedron is a tiling of the plane consisting of two apeirogons.
See 2 and Order-2 apeirogonal tiling
Origin (mathematics)
In mathematics, the origin of a Euclidean space is a special point, usually denoted by the letter O, used as a fixed point of reference for the geometry of the surrounding space.
See 2 and Origin (mathematics)
Oxford University Press
Oxford University Press (OUP) is the publishing house of the University of Oxford.
See 2 and Oxford University Press
Parity (mathematics)
In mathematics, parity is the property of an integer of whether it is even or odd. 2 and parity (mathematics) are integers.
See 2 and Parity (mathematics)
Pascal's triangle
In mathematics, Pascal's triangle is an infinite triangular array of the binomial coefficients which play a crucial role in probability theory, combinatorics, and algebra.
Perfect number
In number theory, a perfect number is a positive integer that is equal to the sum of its positive proper divisors, that is, divisors excluding the number itself.
Persian language
Persian, also known by its endonym Farsi (Fārsī|), is a Western Iranian language belonging to the Iranian branch of the Indo-Iranian subdivision of the Indo-European languages.
Pi
The number (spelled out as "pi") is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159.
See 2 and Pi
Pierpont prime
In number theory, a Pierpont prime is a prime number of the form 2^u\cdot 3^v + 1\, for some nonnegative integers and.
Plane (mathematics)
In mathematics, a plane is a two-dimensional space or flat surface that extends indefinitely.
PlanetMath
PlanetMath is a free, collaborative, mathematics online encyclopedia.
See 2 and PlanetMath
Point (geometry)
In geometry, a point is an abstract idealization of an exact position, without size, in physical space, or its generalization to other kinds of mathematical spaces.
Polygon
In geometry, a polygon is a plane figure made up of line segments connected to form a closed polygonal chain.
See 2 and Polygon
Polygonal number
In mathematics, a polygonal number is a number that counts dots arranged in the shape of a regular polygon.
Polyhedron
In geometry, a polyhedron (polyhedra or polyhedrons) is a three-dimensional shape with flat polygonal faces, straight edges and sharp corners or vertices.
See 2 and Polyhedron
Polynucleotide
In molecular biology, a polynucleotide is a biopolymer composed of nucleotide monomers that are covalently bonded in a chain.
Power of two
A power of two is a number of the form where is an integer, that is, the result of exponentiation with number two as the base and integer as the exponent. 2 and power of two are 2 (number) and integers.
Power set
In mathematics, the power set (or powerset) of a set is the set of all subsets of, including the empty set and itself.
See 2 and Power set
Primary pseudoperfect number
In mathematics, and particularly in number theory, N is a primary pseudoperfect number if it satisfies the Egyptian fraction equation where the sum is over only the prime divisors of N.
See 2 and Primary pseudoperfect number
Prime k-tuple
In number theory, a prime -tuple is a finite collection of values representing a repeatable pattern of differences between prime numbers.
Prime number
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers.
Prime power
In mathematics, a prime power is a positive integer which is a positive integer power of a single prime number.
Prime quadruplet
In number theory, a prime quadruplet (sometimes called prime quadruple) is a set of four prime numbers of the form This represents the closest possible grouping of four primes larger than 3, and is the only prime constellation of length 4.
Prime triplet
In number theory, a prime triplet is a set of three prime numbers in which the smallest and largest of the three differ by 6.
Prime-counting function
In mathematics, the prime-counting function is the function counting the number of prime numbers less than or equal to some real number.
See 2 and Prime-counting function
Primitive abundant number
In mathematics a primitive abundant number is an abundant number whose proper divisors are all deficient numbers.
See 2 and Primitive abundant number
Product topology
In topology and related areas of mathematics, a product space is the Cartesian product of a family of topological spaces equipped with a natural topology called the product topology.
Pronic number
A pronic number is a number that is the product of two consecutive integers, that is, a number of the form n(n+1).
Quaternary numeral system
Quaternary is a numeral system with four as its base.
See 2 and Quaternary numeral system
Radix
In a positional numeral system, the radix (radices) or base is the number of unique digits, including the digit zero, used to represent numbers.
See 2 and Radix
Ramanujan prime
In mathematics, a Ramanujan prime is a prime number that satisfies a result proven by Srinivasa Ramanujan relating to the prime-counting function.
Regular polygon
In Euclidean geometry, a regular polygon is a polygon that is direct equiangular (all angles are equal in measure) and equilateral (all sides have the same length).
Regular polytope
In mathematics, a regular polytope is a polytope whose symmetry group acts transitively on its flags, thus giving it the highest degree of symmetry.
Religion
Religion is a range of social-cultural systems, including designated behaviors and practices, morals, beliefs, worldviews, texts, sanctified places, prophecies, ethics, or organizations, that generally relate humanity to supernatural, transcendental, and spiritual elements—although there is no scholarly consensus over what precisely constitutes a religion.
See 2 and Religion
Roger Heath-Brown
David Rodney "Roger" Heath-Brown (born 12 October 1952) is a British mathematician working in the field of analytic number theory.
Set theory
Set theory is the branch of mathematical logic that studies sets, which can be informally described as collections of objects.
See 2 and Set theory
Silver ratio
In mathematics, two quantities are in the silver ratio (or silver mean) if the ratio of the larger of those two quantities to the smaller quantity is the same as the ratio of the sum of the smaller quantity plus twice the larger quantity to the larger quantity (see below).
Sindhi language
Sindhi (or सिन्धी) is an Indo-Aryan language spoken by about 30 million people in the Pakistani province of Sindh, where it has official status.
Sorani
Sorani Kurdish (rtl, Kurmancîy Xwarû), also known as Central Kurdish, is a Kurdish dialect or a language spoken in Iraq, mainly in Iraqi Kurdistan, as well as the provinces of Kurdistan, Kermanshah, and West Azerbaijan in western Iran.
See 2 and Sorani
Space diagonal
In geometry, a space diagonal (also interior diagonal or body diagonal) of a polyhedron is a line connecting two vertices that are not on the same face.
Sphere
A sphere (from Greek) is a geometrical object that is a three-dimensional analogue to a two-dimensional circle.
See 2 and Sphere
Spirituality
The meaning of spirituality has developed and expanded over time, and various meanings can be found alongside each other.
Springer Science+Business Media
Springer Science+Business Media, commonly known as Springer, is a German multinational publishing company of books, e-books and peer-reviewed journals in science, humanities, technical and medical (STM) publishing.
See 2 and Springer Science+Business Media
Square
In Euclidean geometry, a square is a regular quadrilateral, which means that it has four sides of equal length and four equal angles (90-degree angles, π/2 radian angles, or right angles).
See 2 and Square
Square number
In mathematics, a square number or perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself. 2 and square number are integers.
Square-free element
In mathematics, a square-free element is an element r of a unique factorization domain R that is not divisible by a non-trivial square.
Sublime number
In number theory, a sublime number is a positive integer which has a perfect number of positive factors (including itself), and whose positive factors add up to another perfect number.
Subobject classifier
In category theory, a subobject classifier is a special object Ω of a category such that, intuitively, the subobjects of any object X in the category correspond to the morphisms from X to Ω.
See 2 and Subobject classifier
Subsequence
In mathematics, a subsequence of a given sequence is a sequence that can be derived from the given sequence by deleting some or no elements without changing the order of the remaining elements.
Subtraction
Subtraction (which is signified by the minus sign) is one of the four arithmetic operations along with addition, multiplication and division.
Tamil numerals
The Tamil language has number words and dedicated symbols for them in the Tamil script.
Taylor & Francis
Taylor & Francis Group is an international company originating in England that publishes books and academic journals.
Tessellation
A tessellation or tiling is the covering of a surface, often a plane, using one or more geometric shapes, called tiles, with no overlaps and no gaps.
Tesseract
In geometry, a tesseract or 4-cube is a four-dimensional hypercube, analogous to a two-dimensional square and a three-dimensional cube.
See 2 and Tesseract
Text figures
Text figures (also known as non-lining, lowercase, old style, ranging, hanging, medieval, billing, or antique figures or numerals) are numerals designed with varying heights in a fashion that resembles a typical line of running text, hence the name.
Thai numerals
Thai numerals (เลขไทย) are a set of numerals traditionally used in Thailand, although the Arabic numerals are more common due to extensive westernization of Thailand in the modern Rattanakosin period.
The American Mathematical Monthly
The American Mathematical Monthly is a mathematical journal founded by Benjamin Finkel in 1894.
See 2 and The American Mathematical Monthly
The Mathematical Intelligencer
The Mathematical Intelligencer is a mathematical journal published by Springer Science+Business Media that aims at a conversational and scholarly tone, rather than the technical and specialist tone more common among academic journals.
See 2 and The Mathematical Intelligencer
Thue–Morse sequence
In mathematics, the Thue–Morse or Prouhet–Thue–Morse sequence is the binary sequence (an infinite sequence of 0s and 1s) that can be obtained by starting with 0 and successively appending the Boolean complement of the sequence obtained thus far.
Topological space
In mathematics, a topological space is, roughly speaking, a geometrical space in which closeness is defined but cannot necessarily be measured by a numeric distance.
Triangular number
A triangular number or triangle number counts objects arranged in an equilateral triangle.
Twin prime
A twin prime is a prime number that is either 2 less or 2 more than another prime number—for example, either member of the twin prime pair or In other words, a twin prime is a prime that has a prime gap of two.
See 2 and Twin prime
Uniform tilings in hyperbolic plane
In hyperbolic geometry, a uniform hyperbolic tiling (or regular, quasiregular or semiregular hyperbolic tiling) is an edge-to-edge filling of the hyperbolic plane which has regular polygons as faces and is vertex-transitive (transitive on its vertices, isogonal, i.e. there is an isometry mapping any vertex onto any other).
See 2 and Uniform tilings in hyperbolic plane
Unit vector
In mathematics, a unit vector in a normed vector space is a vector (often a spatial vector) of length 1.
Unitary perfect number
A unitary perfect number is an integer which is the sum of its positive proper unitary divisors, not including the number itself (a divisor d of a number n is a unitary divisor if d and n/d share no common factors).
See 2 and Unitary perfect number
Vertex (geometry)
In geometry, a vertex (vertices or vertexes) is a point where two or more curves, lines, or edges meet or intersect.
Word (computer architecture)
In computing, a word is the natural unit of data used by a particular processor design.
See 2 and Word (computer architecture)
World Scientific
World Scientific Publishing is an academic publisher of scientific, technical, and medical books and journals headquartered in Singapore.
Written Chinese
Written Chinese is a writing system that uses Chinese characters and other symbols to represent the Chinese languages.
X-height
alt.
See 2 and X-height
0
0 (zero) is a number representing an empty quantity. 2 and 0 are integers.
See 2 and 0
1
1 (one, unit, unity) is a number representing a single or the only entity. 2 and 1 are integers.
See 2 and 1
10
10 (ten) is the even natural number following 9 and preceding 11. 2 and 10 are integers.
See 2 and 10
100
100 or one hundred (Roman numeral: C) is the natural number following 99 and preceding 101. 2 and 100 are integers.
See 2 and 100
1024 (number)
1024 is the natural number following 1023 and preceding 1025. 2 and 1024 (number) are integers.
11 (number)
11 (eleven) is the natural number following 10 and preceding 12. 2 and 11 (number) are integers.
12 (number)
12 (twelve) is the natural number following 11 and preceding 13. 2 and 12 (number) are integers.
121 (number)
121 (one hundred twenty-one) is the natural number following 120 and preceding 122. 2 and 121 (number) are integers.
128 (number)
128 (one hundred twenty-eight) is the natural number following 127 and preceding 129. 2 and 128 (number) are integers.
13 (number)
13 (thirteen) is the natural number following 12 and preceding 14. 2 and 13 (number) are integers.
14 (number)
14 (fourteen) is the natural number following 13 and preceding 15. 2 and 14 (number) are integers.
144 (number)
144 (one hundred forty-four) is the natural number following 143 and preceding 145. 2 and 144 (number) are integers.
16 (number)
16 (sixteen) is the natural number following 15 and preceding 17. 2 and 16 (number) are integers.
169 (number)
169 (one hundred sixty-nine) is the natural number following 168 and preceding 170. 2 and 169 (number) are integers.
18 (number)
18 (eighteen) is the natural number following 17 and preceding 19. 2 and 18 (number) are integers.
196 (number)
196 (one hundred ninety-six) is the natural number following 195 and preceding 197. 2 and 196 (number) are integers.
2 BC
Year 2 BC was a common year starting on Thursday or Friday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a common year starting on Wednesday of the Proleptic Julian calendar.
See 2 and 2 BC
20 (number)
20 (twenty; Roman numeral XX) is the natural number following 19 and preceding 21. 2 and 20 (number) are integers.
200 (number)
200 (two hundred) is the natural number following 199 and preceding 201. 2 and 200 (number) are integers.
2000 (number)
It is. 2 and 2000 (number) are integers.
22 (number)
22 (twenty-two) is the natural number following 21 and preceding 23. 2 and 22 (number) are integers.
225 (number)
225 (two hundred twenty-five) is the natural number following 224 and preceding 226. 2 and 225 (number) are integers.
24 (number)
24 (twenty-four) is the natural number following 23 and preceding 25. 2 and 24 (number) are integers.
25 (number)
25 (twenty-five) is the natural number following 24 and preceding 26. 2 and 25 (number) are integers.
256 (number)
256 (two hundred fifty-six) is the natural number following 255 and preceding 257. 2 and 256 (number) are integers.
26 (number)
26 (twenty-six) is the natural number following 25 and preceding 27. 2 and 26 (number) are integers.
28 (number)
28 (twenty-eight) is the natural number following 27 and preceding 29. 2 and 28 (number) are integers.
289 (number)
289 is the natural number following 288 and preceding 290. 2 and 289 (number) are integers.
3
3 (three) is a number, numeral and digit. 2 and 3 are integers.
See 2 and 3
30 (number)
30 (thirty) is the natural number following 29 and preceding 31. 2 and 30 (number) are integers.
300 (number)
300 (three hundred) is the natural number following 299 and preceding 301. 2 and 300 (number) are integers.
32 (number)
32 (thirty-two) is the natural number following 31 and preceding 33. 2 and 32 (number) are integers.
34 (number)
34 (thirty-four) is the natural number following 33 and preceding 35. 2 and 34 (number) are integers.
36 (number)
36 (thirty-six) is the natural number following 35 and preceding 37. 2 and 36 (number) are integers.
38 (number)
38 (thirty-eight) is the natural number following 37 and preceding 39. 2 and 38 (number) are integers.
4
4 (four) is a number, numeral and digit. 2 and 4 are integers.
See 2 and 4
40 (number)
40 (forty) is the natural number following 39 and preceding 41. 2 and 40 (number) are integers.
400 (number)
400 (four hundred) is the natural number following 399 and preceding 401. 2 and 400 (number) are integers.
4000 (number)
4000 (four thousand) is the natural number following 3999 and preceding 4001. 2 and 4000 (number) are integers.
42 (number)
42 (forty-two) is the natural number that follows 41 and precedes 43. 2 and 42 (number) are integers.
44 (number)
44 (forty-four) is the natural number following 43 and preceding 45. 2 and 44 (number) are integers.
46 (number)
46 (forty-six) is the natural number following 45 and preceding 47. 2 and 46 (number) are integers.
48 (number)
48 (forty-eight) is the natural number following 47 and preceding 49. 2 and 48 (number) are integers.
49 (number)
49 (forty-nine) is the natural number following 48 and preceding 50. 2 and 49 (number) are integers.
5
5 (five) is a number, numeral and digit. 2 and 5 are integers.
See 2 and 5
50 (number)
50 (fifty) is the natural number following 49 and preceding 51. 2 and 50 (number) are integers.
512 (number)
512 (five hundred twelve) is the natural number following 511 and preceding 513. 2 and 512 (number) are integers.
6
6 (six) is the natural number following 5 and preceding 7. 2 and 6 are integers.
See 2 and 6
64 (number)
64 (sixty-four) is the natural number following 63 and preceding 65. 2 and 64 (number) are integers.
65,536
65536 is the natural number following 65535 and preceding 65537. 2 and 65,536 are integers.
See 2 and 65,536
67 (number)
67 (sixty-seven) is the natural number following 66 and preceding 68. 2 and 67 (number) are integers.
7
7 (seven) is the natural number following 6 and preceding 8. 2 and 7 are integers.
See 2 and 7
73 (number)
73 (seventy-three) is the natural number following 72 and preceding 74. 2 and 73 (number) are integers.
8
8 (eight) is the natural number following 7 and preceding 9. 2 and 8 are integers.
See 2 and 8
81 (number)
81 (eighty-one) is the natural number following 80 and preceding 82. 2 and 81 (number) are integers.
8192
8192 is the natural number following 8191 and preceding 8193. 2 and 8192 are integers.
See 2 and 8192
9
9 (nine) is the natural number following and preceding. 2 and 9 are integers.
See 2 and 9
See also
2 (number)
- 2
- Area
- Bilingualism
- Binary arithmetic
- Binary chemical weapon
- Binary code
- Binary compounds
- Binary explosives
- Binary form
- Binary function
- Binary image
- Binary option
- Binary search
- Binary trees
- Bipartite (theology)
- Bipedalism
- Bistability
- Bivariate analysis
- Couplet
- Deux-Sèvres
- Dichotomies
- Digon
- Division by two
- Double entendre
- Double stars
- Double-headed eagle
- Doublet (lens)
- Dual (grammatical number)
- Dual diagnosis
- Duets
- Euclidean plane
- GF(2)
- Pair
- Pair (parliamentary convention)
- Pair skating
- Pairing (computing)
- Power of two
- Principle of bivalence
- Problem of two emperors
- Second Holocaust
- Second Triumvirate
- Second circle of hell
- Second-level domains
- Surfaces
- Twisted pair
- Two-dimensional space
- Two-state solution
References
Also known as (II), 1 B1, 1B1, 2 (glyph), 2 (number), 2 (the number), 2**1, 2^1, 2¹, ASCII 50, Brace (hunting), Even prime, II (number), Number 2, Numero dos, Oddest prime, Secondly, Smallest known prime number, Square root of 4, TWO, The 2, The number 2, Twice (adverb), Two (number), Two-ness, U+0032, \x32, , ٢.
, E (mathematical constant), Eastern Arabic numerals, Edge (geometry), Egyptian numerals, Element (mathematics), Empty set, English determiners, English nouns, Equilateral triangle, Euclidean geometry, Euclidean plane, Euclidean space, Euler characteristic, Euler's theorem in geometry, Exponentiation, Face (geometry), Fermat number, Field (mathematics), Fixed point (mathematics), Florida Atlantic University, Forum Geometricorum, Function (mathematics), Geʽez script, Generalized continued fraction, Genus (mathematics), Genus g surface, Georgian numerals, Grammatical gender, Grammatical number, Greek numerals, Gupta script, Hanja, Harmonic divisor number, Harmonic mean, Harshad number, Hebrew numerals, Helium, Hexagon, Highly composite number, Hindustani numerals, Homeomorphism, Hyperoperation, II, Incircle and excircles, Indeterminate form, Infinity, Integer, International Journal of Foundations of Computer Science, Iteration, Japanese writing system, John Horton Conway, Joseph H. Silverman, Kannada script, Khmer numerals, Knuth's up-arrow notation, Labialization, Limit inferior and limit superior, Line (geometry), Logistic map, Look-and-say sequence, Magic constant, Magic number (physics), Magic square, Magic star, Malayalam numerals, Map (mathematics), Mathematical Association of America, Maya numerals, Mersenne prime, Mertens function, Morse code, Multiple (mathematics), Multiplication, Multiplicative inverse, Natural number, Necessity and sufficiency, Nucleic acid double helix, Null set, Number, Number line, Number Two, Numeral (linguistics), Numeral system, Numerical digit, Octagon, Old English, One half, Order-2 apeirogonal tiling, Origin (mathematics), Oxford University Press, Parity (mathematics), Pascal's triangle, Perfect number, Persian language, Pi, Pierpont prime, Plane (mathematics), PlanetMath, Point (geometry), Polygon, Polygonal number, Polyhedron, Polynucleotide, Power of two, Power set, Primary pseudoperfect number, Prime k-tuple, Prime number, Prime power, Prime quadruplet, Prime triplet, Prime-counting function, Primitive abundant number, Product topology, Pronic number, Quaternary numeral system, Radix, Ramanujan prime, Regular polygon, Regular polytope, Religion, Roger Heath-Brown, Set theory, Silver ratio, Sindhi language, Sorani, Space diagonal, Sphere, Spirituality, Springer Science+Business Media, Square, Square number, Square-free element, Sublime number, Subobject classifier, Subsequence, Subtraction, Tamil numerals, Taylor & Francis, Tessellation, Tesseract, Text figures, Thai numerals, The American Mathematical Monthly, The Mathematical Intelligencer, Thue–Morse sequence, Topological space, Triangular number, Twin prime, Uniform tilings in hyperbolic plane, Unit vector, Unitary perfect number, Vertex (geometry), Word (computer architecture), World Scientific, Written Chinese, X-height, 0, 1, 10, 100, 1024 (number), 11 (number), 12 (number), 121 (number), 128 (number), 13 (number), 14 (number), 144 (number), 16 (number), 169 (number), 18 (number), 196 (number), 2 BC, 20 (number), 200 (number), 2000 (number), 22 (number), 225 (number), 24 (number), 25 (number), 256 (number), 26 (number), 28 (number), 289 (number), 3, 30 (number), 300 (number), 32 (number), 34 (number), 36 (number), 38 (number), 4, 40 (number), 400 (number), 4000 (number), 42 (number), 44 (number), 46 (number), 48 (number), 49 (number), 5, 50 (number), 512 (number), 6, 64 (number), 65,536, 67 (number), 7, 73 (number), 8, 81 (number), 8192, 9.