Finding the isomorphism type of an elliptic curveTurning an elliptic curve over C into a complex torusLet E be defined over Fq and let n ≥ 1. Show that E(Fq)[n] and E(Fq)/nE(Fq) have the same order.Isomorphism type of a finite group with respect to multiplication modulo 65Elliptic Curve Group and Multiplicative Inverse of an element.Chinese Remainder theorem on Elliptic Curve groupDetermine Isomorphism typeIsomorphism Type of $mathbbZ_8timesmathbbZ_6timesmathbbZ_4 /langle (2,2,2) rangle$Exercise 3.8b) of Silverman's “Arithmetic of Elliptic Curves”Rank of Elliptic Curve over Finite FieldDistribution of torsion subgroups of elliptic curve

Is aluminum electrical wire used on aircraft?

How to cover method return statement in Apex Class?

Biological Blimps: Propulsion

What if a revenant (monster) gains fire resistance?

A social experiment. What is the worst that can happen?

What is going on with 'gets(stdin)' on the site coderbyte?

15% tax on $7.5k earnings. Is that right?

What does "Scientists rise up against statistical significance" mean? (Comment in Nature)

Is there a RAID 0 Equivalent for RAM?

Pre-mixing cryogenic fuels and using only one fuel tank

Store Credit Card Information in Password Manager?

Yosemite Fire Rings - What to Expect?

What should you do if you miss a job interview (deliberately)?

How does the math work for Perception checks?

Why did the EU agree to delay the Brexit deadline?

Can I say "fingers" when referring to toes?

Does an advisor owe his/her student anything? Will an advisor keep a PhD student only out of pity?

How could a planet have erratic days?

How does a computer interpret real numbers?

Has any country ever had 2 former presidents in jail simultaneously?

Is there an injective, monotonically increasing, strictly concave function from the reals, to the reals?

How do apertures which seem too large to physically fit work?

Picking the different solutions to the time independent Schrodinger eqaution

What is Cash Advance APR?



Finding the isomorphism type of an elliptic curve


Turning an elliptic curve over C into a complex torusLet E be defined over Fq and let n ≥ 1. Show that E(Fq)[n] and E(Fq)/nE(Fq) have the same order.Isomorphism type of a finite group with respect to multiplication modulo 65Elliptic Curve Group and Multiplicative Inverse of an element.Chinese Remainder theorem on Elliptic Curve groupDetermine Isomorphism typeIsomorphism Type of $mathbbZ_8timesmathbbZ_6timesmathbbZ_4 /langle (2,2,2) rangle$Exercise 3.8b) of Silverman's “Arithmetic of Elliptic Curves”Rank of Elliptic Curve over Finite FieldDistribution of torsion subgroups of elliptic curve













0












$begingroup$


Consider the elliptic curve $E: y^2=x^3+1$ over $mathbbF_q$ where $q = 15485863$ (the $1000000^textth$ prime).



I have computed (using sage) that $P=(15065540,4435916)$ has order $5160153 = 3cdot19cdot90529$
and that $|E(mathbbF_q)| = 15480459 = 3^2cdot19cdot90529$



I am asked to find the isomorphism type of $E(mathbbF_q)$, I know from the Fundamental Theorem of Finite Abelian Groups that $E(mathbbF_q) cong mathbbZ/3^2mathbbZ timesmathbbZ/19mathbbZ times mathbbZ/90529mathbbZ$



or that $E(mathbbF_q) cong mathbbZ/3mathbbZ times mathbbZ/3mathbbZtimesmathbbZ/19mathbbZ times mathbbZ/90529mathbbZ$



I would like to know if there's any way that I can discard one of this options. I guess that I would have to find a point of order 9 or at least two points of order 3, but I am not sure how to do this.










share|cite|improve this question









$endgroup$







  • 4




    $begingroup$
    sage will tell you the 3 torsion! you could use P.division_points(3) where P is the origin.
    $endgroup$
    – hunter
    Mar 15 at 4:01










  • $begingroup$
    And you can look at the polynomials such that $[3](x,y) = (fracu(x,y)v(x,y), fracw(x,y)z(x,y))$ then $[3](x,y) = O$ corresponds to the roots of $V(x) = v(x,sqrtx^3+1)v(x,-sqrtx^3+1) in mathbbF_q[x]$.
    $endgroup$
    – reuns
    Mar 15 at 4:27











  • $begingroup$
    @hunter So the 3-torsion points according to what you said and sage are [(0 : 1 : 0), (0 : 1 : 1), (0 : 102 : 1)], this means that there are two points of order 3 and therefore 𝐸(𝔽𝑞)≅ℤ/3ℤ×ℤ/3ℤ×ℤ/19ℤ×ℤ/90529ℤ, right?
    $endgroup$
    – McNuggets666
    Mar 15 at 18:53










  • $begingroup$
    If there's only two points of order 3, then the 3-torsion subgroup must be $mathbbZ/9mathbbZ$, not two copies of $mathbbZ/3mathbbZ$.
    $endgroup$
    – hunter
    Mar 16 at 14:09










  • $begingroup$
    EllipticCurve( GF(nth_prime(1000000)), [0,1] ).order().factor() delivers in sage 2^2 * 3 * 37 * 43 * 811. On the other way, there is a big prime 21843131744681521 obtained by factorizing $y_0^2-x_0^3-1$, where $x_0,y_0$ are the coordinates of $P$.
    $endgroup$
    – dan_fulea
    yesterday















0












$begingroup$


Consider the elliptic curve $E: y^2=x^3+1$ over $mathbbF_q$ where $q = 15485863$ (the $1000000^textth$ prime).



I have computed (using sage) that $P=(15065540,4435916)$ has order $5160153 = 3cdot19cdot90529$
and that $|E(mathbbF_q)| = 15480459 = 3^2cdot19cdot90529$



I am asked to find the isomorphism type of $E(mathbbF_q)$, I know from the Fundamental Theorem of Finite Abelian Groups that $E(mathbbF_q) cong mathbbZ/3^2mathbbZ timesmathbbZ/19mathbbZ times mathbbZ/90529mathbbZ$



or that $E(mathbbF_q) cong mathbbZ/3mathbbZ times mathbbZ/3mathbbZtimesmathbbZ/19mathbbZ times mathbbZ/90529mathbbZ$



I would like to know if there's any way that I can discard one of this options. I guess that I would have to find a point of order 9 or at least two points of order 3, but I am not sure how to do this.










share|cite|improve this question









$endgroup$







  • 4




    $begingroup$
    sage will tell you the 3 torsion! you could use P.division_points(3) where P is the origin.
    $endgroup$
    – hunter
    Mar 15 at 4:01










  • $begingroup$
    And you can look at the polynomials such that $[3](x,y) = (fracu(x,y)v(x,y), fracw(x,y)z(x,y))$ then $[3](x,y) = O$ corresponds to the roots of $V(x) = v(x,sqrtx^3+1)v(x,-sqrtx^3+1) in mathbbF_q[x]$.
    $endgroup$
    – reuns
    Mar 15 at 4:27











  • $begingroup$
    @hunter So the 3-torsion points according to what you said and sage are [(0 : 1 : 0), (0 : 1 : 1), (0 : 102 : 1)], this means that there are two points of order 3 and therefore 𝐸(𝔽𝑞)≅ℤ/3ℤ×ℤ/3ℤ×ℤ/19ℤ×ℤ/90529ℤ, right?
    $endgroup$
    – McNuggets666
    Mar 15 at 18:53










  • $begingroup$
    If there's only two points of order 3, then the 3-torsion subgroup must be $mathbbZ/9mathbbZ$, not two copies of $mathbbZ/3mathbbZ$.
    $endgroup$
    – hunter
    Mar 16 at 14:09










  • $begingroup$
    EllipticCurve( GF(nth_prime(1000000)), [0,1] ).order().factor() delivers in sage 2^2 * 3 * 37 * 43 * 811. On the other way, there is a big prime 21843131744681521 obtained by factorizing $y_0^2-x_0^3-1$, where $x_0,y_0$ are the coordinates of $P$.
    $endgroup$
    – dan_fulea
    yesterday













0












0








0





$begingroup$


Consider the elliptic curve $E: y^2=x^3+1$ over $mathbbF_q$ where $q = 15485863$ (the $1000000^textth$ prime).



I have computed (using sage) that $P=(15065540,4435916)$ has order $5160153 = 3cdot19cdot90529$
and that $|E(mathbbF_q)| = 15480459 = 3^2cdot19cdot90529$



I am asked to find the isomorphism type of $E(mathbbF_q)$, I know from the Fundamental Theorem of Finite Abelian Groups that $E(mathbbF_q) cong mathbbZ/3^2mathbbZ timesmathbbZ/19mathbbZ times mathbbZ/90529mathbbZ$



or that $E(mathbbF_q) cong mathbbZ/3mathbbZ times mathbbZ/3mathbbZtimesmathbbZ/19mathbbZ times mathbbZ/90529mathbbZ$



I would like to know if there's any way that I can discard one of this options. I guess that I would have to find a point of order 9 or at least two points of order 3, but I am not sure how to do this.










share|cite|improve this question









$endgroup$




Consider the elliptic curve $E: y^2=x^3+1$ over $mathbbF_q$ where $q = 15485863$ (the $1000000^textth$ prime).



I have computed (using sage) that $P=(15065540,4435916)$ has order $5160153 = 3cdot19cdot90529$
and that $|E(mathbbF_q)| = 15480459 = 3^2cdot19cdot90529$



I am asked to find the isomorphism type of $E(mathbbF_q)$, I know from the Fundamental Theorem of Finite Abelian Groups that $E(mathbbF_q) cong mathbbZ/3^2mathbbZ timesmathbbZ/19mathbbZ times mathbbZ/90529mathbbZ$



or that $E(mathbbF_q) cong mathbbZ/3mathbbZ times mathbbZ/3mathbbZtimesmathbbZ/19mathbbZ times mathbbZ/90529mathbbZ$



I would like to know if there's any way that I can discard one of this options. I guess that I would have to find a point of order 9 or at least two points of order 3, but I am not sure how to do this.







group-theory finite-groups elliptic-curves






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Mar 15 at 3:55









McNuggets666McNuggets666

723411




723411







  • 4




    $begingroup$
    sage will tell you the 3 torsion! you could use P.division_points(3) where P is the origin.
    $endgroup$
    – hunter
    Mar 15 at 4:01










  • $begingroup$
    And you can look at the polynomials such that $[3](x,y) = (fracu(x,y)v(x,y), fracw(x,y)z(x,y))$ then $[3](x,y) = O$ corresponds to the roots of $V(x) = v(x,sqrtx^3+1)v(x,-sqrtx^3+1) in mathbbF_q[x]$.
    $endgroup$
    – reuns
    Mar 15 at 4:27











  • $begingroup$
    @hunter So the 3-torsion points according to what you said and sage are [(0 : 1 : 0), (0 : 1 : 1), (0 : 102 : 1)], this means that there are two points of order 3 and therefore 𝐸(𝔽𝑞)≅ℤ/3ℤ×ℤ/3ℤ×ℤ/19ℤ×ℤ/90529ℤ, right?
    $endgroup$
    – McNuggets666
    Mar 15 at 18:53










  • $begingroup$
    If there's only two points of order 3, then the 3-torsion subgroup must be $mathbbZ/9mathbbZ$, not two copies of $mathbbZ/3mathbbZ$.
    $endgroup$
    – hunter
    Mar 16 at 14:09










  • $begingroup$
    EllipticCurve( GF(nth_prime(1000000)), [0,1] ).order().factor() delivers in sage 2^2 * 3 * 37 * 43 * 811. On the other way, there is a big prime 21843131744681521 obtained by factorizing $y_0^2-x_0^3-1$, where $x_0,y_0$ are the coordinates of $P$.
    $endgroup$
    – dan_fulea
    yesterday












  • 4




    $begingroup$
    sage will tell you the 3 torsion! you could use P.division_points(3) where P is the origin.
    $endgroup$
    – hunter
    Mar 15 at 4:01










  • $begingroup$
    And you can look at the polynomials such that $[3](x,y) = (fracu(x,y)v(x,y), fracw(x,y)z(x,y))$ then $[3](x,y) = O$ corresponds to the roots of $V(x) = v(x,sqrtx^3+1)v(x,-sqrtx^3+1) in mathbbF_q[x]$.
    $endgroup$
    – reuns
    Mar 15 at 4:27











  • $begingroup$
    @hunter So the 3-torsion points according to what you said and sage are [(0 : 1 : 0), (0 : 1 : 1), (0 : 102 : 1)], this means that there are two points of order 3 and therefore 𝐸(𝔽𝑞)≅ℤ/3ℤ×ℤ/3ℤ×ℤ/19ℤ×ℤ/90529ℤ, right?
    $endgroup$
    – McNuggets666
    Mar 15 at 18:53










  • $begingroup$
    If there's only two points of order 3, then the 3-torsion subgroup must be $mathbbZ/9mathbbZ$, not two copies of $mathbbZ/3mathbbZ$.
    $endgroup$
    – hunter
    Mar 16 at 14:09










  • $begingroup$
    EllipticCurve( GF(nth_prime(1000000)), [0,1] ).order().factor() delivers in sage 2^2 * 3 * 37 * 43 * 811. On the other way, there is a big prime 21843131744681521 obtained by factorizing $y_0^2-x_0^3-1$, where $x_0,y_0$ are the coordinates of $P$.
    $endgroup$
    – dan_fulea
    yesterday







4




4




$begingroup$
sage will tell you the 3 torsion! you could use P.division_points(3) where P is the origin.
$endgroup$
– hunter
Mar 15 at 4:01




$begingroup$
sage will tell you the 3 torsion! you could use P.division_points(3) where P is the origin.
$endgroup$
– hunter
Mar 15 at 4:01












$begingroup$
And you can look at the polynomials such that $[3](x,y) = (fracu(x,y)v(x,y), fracw(x,y)z(x,y))$ then $[3](x,y) = O$ corresponds to the roots of $V(x) = v(x,sqrtx^3+1)v(x,-sqrtx^3+1) in mathbbF_q[x]$.
$endgroup$
– reuns
Mar 15 at 4:27





$begingroup$
And you can look at the polynomials such that $[3](x,y) = (fracu(x,y)v(x,y), fracw(x,y)z(x,y))$ then $[3](x,y) = O$ corresponds to the roots of $V(x) = v(x,sqrtx^3+1)v(x,-sqrtx^3+1) in mathbbF_q[x]$.
$endgroup$
– reuns
Mar 15 at 4:27













$begingroup$
@hunter So the 3-torsion points according to what you said and sage are [(0 : 1 : 0), (0 : 1 : 1), (0 : 102 : 1)], this means that there are two points of order 3 and therefore 𝐸(𝔽𝑞)≅ℤ/3ℤ×ℤ/3ℤ×ℤ/19ℤ×ℤ/90529ℤ, right?
$endgroup$
– McNuggets666
Mar 15 at 18:53




$begingroup$
@hunter So the 3-torsion points according to what you said and sage are [(0 : 1 : 0), (0 : 1 : 1), (0 : 102 : 1)], this means that there are two points of order 3 and therefore 𝐸(𝔽𝑞)≅ℤ/3ℤ×ℤ/3ℤ×ℤ/19ℤ×ℤ/90529ℤ, right?
$endgroup$
– McNuggets666
Mar 15 at 18:53












$begingroup$
If there's only two points of order 3, then the 3-torsion subgroup must be $mathbbZ/9mathbbZ$, not two copies of $mathbbZ/3mathbbZ$.
$endgroup$
– hunter
Mar 16 at 14:09




$begingroup$
If there's only two points of order 3, then the 3-torsion subgroup must be $mathbbZ/9mathbbZ$, not two copies of $mathbbZ/3mathbbZ$.
$endgroup$
– hunter
Mar 16 at 14:09












$begingroup$
EllipticCurve( GF(nth_prime(1000000)), [0,1] ).order().factor() delivers in sage 2^2 * 3 * 37 * 43 * 811. On the other way, there is a big prime 21843131744681521 obtained by factorizing $y_0^2-x_0^3-1$, where $x_0,y_0$ are the coordinates of $P$.
$endgroup$
– dan_fulea
yesterday




$begingroup$
EllipticCurve( GF(nth_prime(1000000)), [0,1] ).order().factor() delivers in sage 2^2 * 3 * 37 * 43 * 811. On the other way, there is a big prime 21843131744681521 obtained by factorizing $y_0^2-x_0^3-1$, where $x_0,y_0$ are the coordinates of $P$.
$endgroup$
– dan_fulea
yesterday










0






active

oldest

votes











Your Answer





StackExchange.ifUsing("editor", function ()
return StackExchange.using("mathjaxEditing", function ()
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
);
);
, "mathjax-editing");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "69"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);













draft saved

draft discarded


















StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3148871%2ffinding-the-isomorphism-type-of-an-elliptic-curve%23new-answer', 'question_page');

);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes















draft saved

draft discarded
















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid


  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.

Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3148871%2ffinding-the-isomorphism-type-of-an-elliptic-curve%23new-answer', 'question_page');

);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

How should I support this large drywall patch? Planned maintenance scheduled April 23, 2019 at 00:00UTC (8:00pm US/Eastern) Announcing the arrival of Valued Associate #679: Cesar Manara Unicorn Meta Zoo #1: Why another podcast?How do I cover large gaps in drywall?How do I keep drywall around a patch from crumbling?Can I glue a second layer of drywall?How to patch long strip on drywall?Large drywall patch: how to avoid bulging seams?Drywall Mesh Patch vs. Bulge? To remove or not to remove?How to fix this drywall job?Prep drywall before backsplashWhat's the best way to fix this horrible drywall patch job?Drywall patching using 3M Patch Plus Primer

random experiment with two different functions on unit interval Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 23, 2019 at 00:00UTC (8:00pm US/Eastern)Random variable and probability space notionsRandom Walk with EdgesFinding functions where the increase over a random interval is Poisson distributedNumber of days until dayCan an observed event in fact be of zero probability?Unit random processmodels of coins and uniform distributionHow to get the number of successes given $n$ trials , probability $P$ and a random variable $X$Absorbing Markov chain in a computer. Is “almost every” turned into always convergence in computer executions?Stopped random walk is not uniformly integrable

Lowndes Grove History Architecture References Navigation menu32°48′6″N 79°57′58″W / 32.80167°N 79.96611°W / 32.80167; -79.9661132°48′6″N 79°57′58″W / 32.80167°N 79.96611°W / 32.80167; -79.9661178002500"National Register Information System"Historic houses of South Carolina"Lowndes Grove""+32° 48' 6.00", −79° 57' 58.00""Lowndes Grove, Charleston County (260 St. Margaret St., Charleston)""Lowndes Grove"The Charleston ExpositionIt Happened in South Carolina"Lowndes Grove (House), Saint Margaret Street & Sixth Avenue, Charleston, Charleston County, SC(Photographs)"Plantations of the Carolina Low Countrye