Primitive Roots and Unit Groups Modulo N — Examples
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✓ 11 results · all verified · 4 also independently AI-judged
Every result on this page is machine-checked by a proof checker and read in full and owner-audited; the judge is an additional, independent cross-model AI review of the proofs. The 7 not AI-judged were verified by owner audit (typically over a confirmed judge false positive), not failures.
1 · Prerequisites
Abstract Algebra
- Binary Operations, Monoids, Groups and Subgroups
- Cosets, Index and Lagrange's Theorem
- Cyclic Groups and Direct Products
- Group Homomorphisms and the Isomorphism Theorems
- Normal Subgroups and Quotient Groups
- Polynomial Rings, the Division Algorithm and Roots
- Rings, Subrings, Integral Domains and Fields
- The Fundamental Theorem of Finite Abelian Groups
Number Theory
Real Analysis
2 · Logical flowchart
3 · Items
Example
The primitive roots modulo 17 are 3,5,6,7,10,11,12,14
Example
An index table modulo 17 turns multiplication into addition modulo 16
Example
2 is a primitive root modulo 13 by testing the prime divisors of 12
Example
2 is primitive modulo every power of 5
Example
The unit group modulo 240 decomposes as C₂²× C₄²
Example
λ(561)=80 and every integer coprime to 561 has eightieth power congruent to one
Example
λ(1729)=36 although φ(1729)=1296
Counterexample
(ℤ/15ℤ)^× has order 8 but is not cyclic
Counterexample
φ(8)=4 but every unit modulo 8 has square one
Example
The four square roots of one modulo 128 are 1,63,65,127
Example
The positive moduli below 20 admitting primitive roots are 1,2,3,4,5,6,7,9,10,11,13,14,17,18,19
Sources
- William Stein, Elementary Number Theory, Example 2.5.13
- Peter Hackman, Elementary Number Theory, Example C.I.2
- William Stein, Elementary Number Theory, Example 2.5.9
- William Stein, Elementary Number Theory, Theorem 2.5.11
- Peter Hackman, Elementary Number Theory, Example C.V.1
- William Stein, Elementary Number Theory, §2.5
- William Stein, Elementary Number Theory, Example 2.5.10
- Peter Hackman, Elementary Number Theory, Example C.IV.9