Field theory and polynomials Proof
Proof that the multiplicative group of a finite field is cyclic
Builds on Finite fieldGroup of units of a ringFinite subgroups of the multiplicative group of a field are cyclic
Proof
- Let be a finite field of order , and let be its group of units.
- In a field, every nonzero element is a unit. So has elements.
- So is a finite subgroup of the multiplicative group of the field .
- By the theorem on finite subgroups of , with and , the group is cyclic.
- By step 2, it is cyclic of order .
Idea
The whole group is itself a finite subgroup of the multiplicative group of . So the general theorem applies to it directly.
Reading path
To understand this page from the ground up, read these 139 pages in order. The foundations come first. The path takes the proofs Proof of Bézout's identity, Proof of cancellation in an integral domain, Proof of the generalized Euclid's lemma, Proof of the commutativity of addition by induction, Proof that equivalence classes form a partition, Proof that g to the n equals 1 iff the order divides n, Proof that R[x] is an integral domain iff R is, Proof that g to the order of the group is the identity, Proof that finite subgroups of the multiplicative group of a field are cyclic, Proof that the order of an element divides the order of the group, Proof of the degree of a product over an integral domain, Proof of strong induction from ordinary induction, Proof of the laws of exponents in a group, Proof that a product of two finite cyclic groups is cyclic iff their orders are coprime, Proof that a polynomial over a field has at most as many roots as its degree, Proof of the remainder theorem, Proof that a finite abelian group is cyclic iff its exponent equals its order, Proof that the order of a cyclic subgroup equals the order of its generator, Proof of the well-ordering principle from strong induction, Proof of the division algorithm, Proof of the uniqueness of inverses, Proof that cyclic groups of the same order are isomorphic, Proof of Lagrange's theorem, Proof of the factor theorem, Proof that cosets have the same cardinality as the subgroup.
- Binary operation definition
- Definition by recursion concept
- Divisibility definition
- Element definition
- Group concept
- Left coset concept
- Mathematical induction concept
- Natural numbers object
- Peano axioms concept
- Proposition concept
- Vector space definition
- Commutativity definition
- Identity element definition
- Greatest common divisor definition
- Set definition
- Direct product of groups definition
- Group homomorphism definition
- Order of a group definition
- Ring definition
- Subgroup definition
- Successor function definition
- Conjunction definition
- Disjunction definition
- Implication definition
- Predicate definition
- External direct sum definition
- Inverse element definition
- Abelian group definition
- Coprime integers definition
- Empty set object
- Family of sets definition
- Ordered pair definition
- Group isomorphism definition
- Intersection definition
- Addition of natural numbers definition
- Union definition
- Commutative ring definition
- Polynomial ring definition
- Ring homomorphism definition
- Unit of a ring definition
- Zero divisor definition
- Left coset definition
- Right coset definition
- Set-builder notation concept
- The successor function is injective statement
- Zero is not a successor statement
- Biconditional definition
- Existential quantifier definition
- Universal quantifier definition
- Proof of the uniqueness of inverses proof
- Cartesian product definition
- Disjoint sets definition
- Order on the natural numbers definition
- Proof of the commutativity of addition by induction proof
- Group of units of a ring definition
- Divisibility in a commutative ring definition
- Subset definition
- Degree of a polynomial definition
- Polynomial evaluation definition
- Union of a family of sets definition
- Field definition
- Axiom of extensionality statement
- Integral domain definition
- Uniqueness quantifier definition
- Uniqueness of inverses statement
- Binary relation definition
- Commutativity of addition statement
- Partition of a set definition
- Leading coefficient definition
- Root of a polynomial definition
- Proof of cancellation in an integral domain proof
- Evaluation homomorphism definition
- Proof of strong induction from ordinary induction proof
- Finite field definition
- Reflexive relation definition
- Symmetric relation definition
- Transitive relation definition
- Proof of the laws of exponents in a group proof
- Monic polynomial definition
- Strong induction statement
- Multiplicity of a root definition
- Function definition
- Proof of the degree of a product over an integral domain proof
- Proof of the remainder theorem proof
- Cancellation in an integral domain statement
- Equivalence relation definition
- Laws of exponents in a group statement
- Proof of the well-ordering principle from strong induction proof
- Codomain definition
- Injective function definition
- Division algorithm for polynomials statement
- Degree of a product statement
- Order of an element definition
- Well-ordering principle statement
- Cyclic subgroup generated by an element definition
- Surjective function definition
- Remainder theorem statement
- Equivalence class definition
- Proof that R[x] is an integral domain iff R is proof
- Exponent of a group definition
- Proof of the division algorithm proof
- Cyclic group definition
- Bijective function definition
- Proof that equivalence classes form a partition proof
- Proof of the factor theorem proof
- R[x] is an integral domain iff R is statement
- Division algorithm statement
- Equinumerous sets definition
- Equivalence classes form a partition statement
- Factor theorem statement
- Cardinality definition
- Proof of Bézout's identity proof
- Proof that g to the n equals 1 iff the order divides n proof
- Proof that a polynomial over a field has at most as many roots as its degree proof
- g to the n equals 1 iff the order divides n statement
- Bézout's identity statement
- A polynomial over a field has at most as many roots as its degree statement
- Proof that cosets have the same cardinality as the subgroup proof
- Proof of the generalized Euclid's lemma proof
- Proof that the order of a cyclic subgroup equals the order of its generator proof
- Cosets have the same cardinality as the subgroup statement
- Generalized Euclid's lemma statement
- Order of a cyclic subgroup equals the order of its generator statement
- Proof of Lagrange's theorem proof
- Proof that a product of two finite cyclic groups is cyclic iff their orders are coprime proof
- Proof that cyclic groups of the same order are isomorphic proof
- Lagrange's theorem statement
- Proof that the order of an element divides the order of the group proof
- Cyclic groups of the same order are isomorphic statement
- Product of cyclic groups is cyclic iff the orders are coprime statement
- Order of an element divides the order of the group statement
- Proof that g to the order of the group is the identity proof
- Classification of finite abelian groups statement
- g to the order of the group is the identity statement
- Proof that a finite abelian group is cyclic iff its exponent equals its order proof
- A finite abelian group is cyclic iff its exponent equals its order statement
- Proof that finite subgroups of the multiplicative group of a field are cyclic proof
- Finite subgroups of the multiplicative group of a field are cyclic statement
- Proof that the multiplicative group of a finite field is cyclic proof
Where this leads
16 pages build on this one.
- Uniqueness of finite fields of a given order
- Galois field
- The multiplicative group of a finite field is cyclic
- Primitive element theorem
- Fundamental theorem of Galois theory
- Gauss–Wantzel theorem
- Primitive element of a finite field
- Primitive polynomial over a finite field
- Weil conjectures
- Proof of the uniqueness of finite fields of a given order
- Standard conjectures on algebraic cycles
- Proof of the primitive element theorem
- Galois group of a finite field extension
- Proof of the fundamental theorem of Galois theory
- Proof of the Gauss–Wantzel theorem
- Artin's theorem on fixed fields
Further reading
- Web https://en.wikipedia.org/wiki/Finite_field, Multiplicative structure
About this page
| Tag | XXV5KB8CF0 |
|---|---|
| URI | m2://XXV5KB8CF0 |
| Kind | proof |
| Writing | W0 stub |
| MSC | 12E20 |
| Proves | The multiplicative group of a finite field is cyclic |
| Uses | Finite field, Group of units of a ring, Finite subgroups of the multiplicative group of a field are cyclic |
| Changed | 4 November 2026 |
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