FrobeniusAutomorphism
gives the value of the Frobenius automorphism at the finite field element a.
gives the value of the kth functional power of the Frobenius automorphism at a.
Details
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- For a finite field
with characteristic
, the Frobenius automorphism is given by
.
- All finite field automorphisms are functional powers of the Frobenius automorphism.
- The number of different field automorphisms of
is equal to the extension degree of
over
.
- Any field automorphism
satisfies equations
and
.
- If n is the degree of the MinimalPolynomial f of an element a of
, then Table[FrobeniusAutomorphism[a,k],{k,n}] gives all the roots of f in
.
Examples
open allclose allBasic Examples (1)
Scope (1)
Applications (1)
Compute the minimal polynomial of an element of a finite field:
The minimal polynomial of is the product of
over all conjugates
of
:
Convert to integer coefficients:
Compare with the result obtained using the built-in MinimalPolynomial:
Properties & Relations (5)
Frobenius automorphism is a field automorphism:
For a finite field with characteristic
, the Frobenius automorphism is given by
:
All finite field automorphisms are functional powers of the Frobenius automorphism:
Use FiniteFieldEmbedding to find an automorphism of :
Identify the functional power of the Frobenius automorphism that gives the same mapping:
The number of different field automorphisms of is equal to the extension degree of
over
:
Compute all conjugates of a finite field element a:
The absolute trace of a is equal to the sum of conjugates:
Use FiniteFieldElementTrace to compute the absolute trace:
The absolute norm of a is equal to the product of conjugates:
Use FiniteFieldElementNorm to compute the absolute norm:
The conjugates are roots of MinimalPolynomial[a]:
Text
Wolfram Research (2023), FrobeniusAutomorphism, Wolfram Language function, https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html.
CMS
Wolfram Language. 2023. "FrobeniusAutomorphism." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html.
APA
Wolfram Language. (2023). FrobeniusAutomorphism. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html