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Finite fields (also called Galois fields) are fields with finitely many elements, whose number is also referred to as the order of the field. The above introductory example F 4 is a field with four elements. Its subfield F 2 is the smallest field, because by definition a field has at least two distinct elements, 0 and 1.
A field has a consistent tensorial character wherever it is defined: i.e. a field cannot be a scalar field somewhere and a vector field somewhere else. For example, the Newtonian gravitational field is a vector field: specifying its value at a point in spacetime requires three numbers, the components of the gravitational field vector at that point.
In mathematics, a finite field or Galois field (so-named in honor of Évariste Galois) is a field that contains a finite number of elements.As with any field, a finite field is a set on which the operations of multiplication, addition, subtraction and division are defined and satisfy certain basic rules.
Mathematically, a scalar field on a region U is a real or complex-valued function or distribution on U. [1] [2] The region U may be a set in some Euclidean space, Minkowski space, or more generally a subset of a manifold, and it is typical in mathematics to impose further conditions on the field, such that it be continuous or often continuously differentiable to some order.
For fields E and F, these properties imply that f(0) = 0, f(x −1) = f(x) −1 for x in E ×, and that f is injective. Fields, together with these homomorphisms, form a category . Two fields E and F are called isomorphic if there exists a bijective homomorphism
An alternative definition: A smooth vector field on a manifold is a linear map : () such that is a derivation: () = + for all , (). [ 3 ] If the manifold M {\displaystyle M} is smooth or analytic —that is, the change of coordinates is smooth (analytic)—then one can make sense of the notion of smooth (analytic) vector fields.
The field L is a normal extension if and only if any of the equivalent conditions below hold. The minimal polynomial over K of every element in L splits in L ; There is a set S ⊆ K [ x ] {\displaystyle S\subseteq K[x]} of polynomials that each splits over L , such that if K ⊆ F ⊊ L {\displaystyle K\subseteq F\subsetneq L} are fields, then ...
Perfect fields are significant because Galois theory over these fields becomes simpler, since the general Galois assumption of field extensions being separable is automatically satisfied over these fields (see third condition above). Another important property of perfect fields is that they admit Witt vectors.