Exercise 4.11 Allufi












1














This exercise is on page 69 of Algebra chapter 0.



Problem:




In due time we will prove the easy fact that if $p$ is a prime integer, then the equation $x^d = 1$ can have at most $d$ solutions in $mathbb{Z}/pmathbb{Z}$. Assume this fact, and prove that the multiplicative group $G =(mathbb{Z}/pmathbb{Z})^{ast}$ is cyclic.




Attempt:



Using the this fact along with another exercise one can show that $h^{|g|} = 1$ for $g in G$ element of maximal order. This shows that for all $|h| leq |g|$ for all $h in G$. We can also show that $|g| leq |G| = p - 1$.
I am not sure how can we show that $|G| leq |g|$ though ? I don't want to use Lagrange theorem as we don't know this result yet in the book.










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  • See this question.
    – Dietrich Burde
    Dec 26 '18 at 20:51










  • See this theorem.
    – Bill Dubuque
    Dec 27 '18 at 2:23
















1














This exercise is on page 69 of Algebra chapter 0.



Problem:




In due time we will prove the easy fact that if $p$ is a prime integer, then the equation $x^d = 1$ can have at most $d$ solutions in $mathbb{Z}/pmathbb{Z}$. Assume this fact, and prove that the multiplicative group $G =(mathbb{Z}/pmathbb{Z})^{ast}$ is cyclic.




Attempt:



Using the this fact along with another exercise one can show that $h^{|g|} = 1$ for $g in G$ element of maximal order. This shows that for all $|h| leq |g|$ for all $h in G$. We can also show that $|g| leq |G| = p - 1$.
I am not sure how can we show that $|G| leq |g|$ though ? I don't want to use Lagrange theorem as we don't know this result yet in the book.










share|cite|improve this question
























  • See this question.
    – Dietrich Burde
    Dec 26 '18 at 20:51










  • See this theorem.
    – Bill Dubuque
    Dec 27 '18 at 2:23














1












1








1







This exercise is on page 69 of Algebra chapter 0.



Problem:




In due time we will prove the easy fact that if $p$ is a prime integer, then the equation $x^d = 1$ can have at most $d$ solutions in $mathbb{Z}/pmathbb{Z}$. Assume this fact, and prove that the multiplicative group $G =(mathbb{Z}/pmathbb{Z})^{ast}$ is cyclic.




Attempt:



Using the this fact along with another exercise one can show that $h^{|g|} = 1$ for $g in G$ element of maximal order. This shows that for all $|h| leq |g|$ for all $h in G$. We can also show that $|g| leq |G| = p - 1$.
I am not sure how can we show that $|G| leq |g|$ though ? I don't want to use Lagrange theorem as we don't know this result yet in the book.










share|cite|improve this question















This exercise is on page 69 of Algebra chapter 0.



Problem:




In due time we will prove the easy fact that if $p$ is a prime integer, then the equation $x^d = 1$ can have at most $d$ solutions in $mathbb{Z}/pmathbb{Z}$. Assume this fact, and prove that the multiplicative group $G =(mathbb{Z}/pmathbb{Z})^{ast}$ is cyclic.




Attempt:



Using the this fact along with another exercise one can show that $h^{|g|} = 1$ for $g in G$ element of maximal order. This shows that for all $|h| leq |g|$ for all $h in G$. We can also show that $|g| leq |G| = p - 1$.
I am not sure how can we show that $|G| leq |g|$ though ? I don't want to use Lagrange theorem as we don't know this result yet in the book.







abstract-algebra group-theory polynomials cyclic-groups






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edited Dec 27 '18 at 0:56









the_fox

2,43411431




2,43411431










asked Dec 26 '18 at 20:37









Newbie

426211




426211












  • See this question.
    – Dietrich Burde
    Dec 26 '18 at 20:51










  • See this theorem.
    – Bill Dubuque
    Dec 27 '18 at 2:23


















  • See this question.
    – Dietrich Burde
    Dec 26 '18 at 20:51










  • See this theorem.
    – Bill Dubuque
    Dec 27 '18 at 2:23
















See this question.
– Dietrich Burde
Dec 26 '18 at 20:51




See this question.
– Dietrich Burde
Dec 26 '18 at 20:51












See this theorem.
– Bill Dubuque
Dec 27 '18 at 2:23




See this theorem.
– Bill Dubuque
Dec 27 '18 at 2:23










1 Answer
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If $mid gmidlt mid Gmid=p-1$, then $x^{mid gmid}=1$ has $p-1gtmid gmid$ solutions. This contradicts the fact you were given about $x^d=1$.






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    If $mid gmidlt mid Gmid=p-1$, then $x^{mid gmid}=1$ has $p-1gtmid gmid$ solutions. This contradicts the fact you were given about $x^d=1$.






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      If $mid gmidlt mid Gmid=p-1$, then $x^{mid gmid}=1$ has $p-1gtmid gmid$ solutions. This contradicts the fact you were given about $x^d=1$.






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        If $mid gmidlt mid Gmid=p-1$, then $x^{mid gmid}=1$ has $p-1gtmid gmid$ solutions. This contradicts the fact you were given about $x^d=1$.






        share|cite|improve this answer












        If $mid gmidlt mid Gmid=p-1$, then $x^{mid gmid}=1$ has $p-1gtmid gmid$ solutions. This contradicts the fact you were given about $x^d=1$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 27 '18 at 4:10









        Chris Custer

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