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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

  • 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

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Basic Examples  (1)Summary of the most common use cases

Represent a finite field with characteristic and extension degree :

Out[1]=1

Compute the value of the Frobenius automorphism at an element of the field:

Out[2]=2
Out[3]=3

The third functional power of the Frobenius automorphism:

Out[4]=4
Out[5]=5

Scope  (1)Survey of the scope of standard use cases

Compute the value of the Frobenius automorphism at an element of a finite field:

Out[3]=3

Compute all conjugates of a:

Out[4]=4

Conjugates of a are roots of the minimal polynomial of a:

Out[5]=5

Applications  (1)Sample problems that can be solved with this function

Compute the minimal polynomial of an element of a finite field:

Out[2]=2

The minimal polynomial of is the product of over all conjugates of :

Out[3]=3

Convert to integer coefficients:

Out[4]=4

Compare with the result obtained using the built-in MinimalPolynomial:

Out[5]=5

Properties & Relations  (5)Properties of the function, and connections to other functions

Frobenius automorphism is a field automorphism:

Out[2]=2
Out[3]=3
Out[4]=4

For a finite field with characteristic , the Frobenius automorphism is given by :

Out[1]=1
Out[2]=2

All finite field automorphisms are functional powers of the Frobenius automorphism:

Out[1]=1

Use FiniteFieldEmbedding to find an automorphism of :

Out[2]=2

Identify the functional power of the Frobenius automorphism that gives the same mapping:

Out[3]=3
Out[4]=4

The number of different field automorphisms of is equal to the extension degree of over :

Out[1]=1
Out[2]=2
Out[3]=3

Compute all conjugates of a finite field element a:

Out[1]=1

The absolute trace of a is equal to the sum of conjugates:

Out[2]=2

Use FiniteFieldElementTrace to compute the absolute trace:

Out[3]=3

The absolute norm of a is equal to the product of conjugates:

Out[4]=4

Use FiniteFieldElementNorm to compute the absolute norm:

Out[5]=5

The conjugates are roots of MinimalPolynomial[a]:

Out[6]=6
Wolfram Research (2023), FrobeniusAutomorphism, Wolfram Language function, https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html.
Wolfram Research (2023), FrobeniusAutomorphism, Wolfram Language function, https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html.

Text

Wolfram Research (2023), FrobeniusAutomorphism, Wolfram Language function, https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html.

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.

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

Wolfram Language. (2023). FrobeniusAutomorphism. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html

BibTeX

@misc{reference.wolfram_2025_frobeniusautomorphism, author="Wolfram Research", title="{FrobeniusAutomorphism}", year="2023", howpublished="\url{https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html}", note=[Accessed: 04-April-2025 ]}

@misc{reference.wolfram_2025_frobeniusautomorphism, author="Wolfram Research", title="{FrobeniusAutomorphism}", year="2023", howpublished="\url{https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html}", note=[Accessed: 04-April-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_frobeniusautomorphism, organization={Wolfram Research}, title={FrobeniusAutomorphism}, year={2023}, url={https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html}, note=[Accessed: 04-April-2025 ]}

@online{reference.wolfram_2025_frobeniusautomorphism, organization={Wolfram Research}, title={FrobeniusAutomorphism}, year={2023}, url={https://reference.wolfram.com/language/ref/FrobeniusAutomorphism.html}, note=[Accessed: 04-April-2025 ]}