Category
page 1Field theory
rational number
quotient of two integers
field
commutative ring in which every nonzero element is inversible
fundamental theorem of algebra
Every polynomial has a real or complex root
Archimedean property
the absence of infinitesimals in a mathematical system
algebraic number field
a finite degree (and hence algebraic) field extension of the field of rational numbers
p-adic number
number system for a prime p which extends the ordinary arithmetic of the rational numbers in a different way from the extension of the rational number system to the real and complex number systems
hyperreal number
element of a nonstandard model of the reals, which can be infinite or infinitesimal
characteristic
in a field or a ring, the smallest positive integer, if any, such that the sum of n ones equals 0; zero otherwise
algebraically closed field
field in which every polynomial is factorizable into monomials
splitting field
minimal field in which every polynomial in a given set decomposes into linear factors
field of fractions
smallest field in which an integral domain can be embedded
Eisenstein's criterion
theorem
algebraic independence
linearly independence of elements of a field extension that are also not related via finitary arithmetic operations
algebraic element
element of an extension field which is a root of a non-zero polynomial with coefficients in the subfield
quadratic field
algebraic number field of degree two over the rational numbers
minimal polynomial
given an element α of a field extension E/F, the unique monic polynomial p∈F[x] of minimal degree such that p(α) = 0
Iwasawa theory
study of objects of arithmetic interest over infinite towers of number fields
valuation
function in algebra which generalises the concept of multiplicity for commutative rings
global field
mathematical concept
superreal number
class of extensions of the real numbers
perfect field
a field that is either of characteristic 0, or of positive characteristic p such that every element admits a p-th root
local field
non-discrete locally compact topological field
Tschirnhaus transformation
mathematical term; type of polynomial transformation
primitive element theorem
Field theory theorem
Conjugate element
another root of the same minimal polynomial
separable polynomial
expression whose number of distinct roots is equal to its degree
multiplicative group
several notions
Kummer theory
mathematical theory describing field extensions involving the adjunction of nth roots
Lüroth's theorem
subfield of K(X) is isomorphic to K(X)
valuation ring
Concept in algebra
Field trace
Mathematical function
euclidean field
ordered field where every nonnegative element is a square
transcendental extension
field extension that contains an element algebraically independent from the base field
Pythagorean field
field in which every sum of two squares is a square
rupture field
minimal field extension containing at least one root of an irreducible polynomial
primitive polynomial
the minimal polynomial of a primitive element of a finite field regarded as a field extension over a finite field of prime order
discrete valuation
a valuation on a field taking values in the integers
Pythagoras number
complete field
algebraic structure that is complete relative to a metric
algebraic function field
finitely generated extension field of positive transcendence degree
totally real number field
a number field K such that, for each embedding of K into the complex numbers, the image lies inside the real numbers
Composite field
Liouville's theorem
theorem in differential algebra

function field of an algebraic variety
the field of ratios of polynomial functions on a variety
quadratically closed field
field in which every element of the field has a square root in the field
formally real field
field that can be equipped with an ordering