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Mazur's theorem on torsion of elliptic curves (Theorem)
Theorem 1 (Mazur)   Let $ E/\mathbb{Q}$ be an elliptic curve. Then the torsion subgroup $ E_{\operatorname{torsion}}(\mathbb{Q})$ is exactly one of the following groups:
$\displaystyle \mathbb{Z}/N\mathbb{Z}\quad 1\leq N \leq 10\quad or\quad N=12$
$\displaystyle \mathbb{Z}/2 \mathbb{Z}\oplus \mathbb{Z}/ 2N \mathbb{Z}\quad 1\leq N\leq 4$

Note: see Nagell-Lutz theorem for an efficient algorithm to compute the torsion subgroup of an elliptic curve defined over $ \mathbb{Q}$.

Bibliography

1
Joseph H. Silverman, The Arithmetic of Elliptic Curves. Springer-Verlag, New York, 1986.
2
Barry Mazur, Modular curves and the Eisenstein ideal, IHES Publ. Math. 47 (1977), 33-186.
3
Barry Mazur, Rational isogenies of prime degree, Invent. Math. 44 (1978), 129-162.



"Mazur's theorem on torsion of elliptic curves" is owned by alozano.
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See Also: elliptic curve, Mordell-Weil theorem, rank of an elliptic curve, the torsion subgroup of an elliptic curve injects in the reduction of the curve, the arithmetic of elliptic curves

Also defines:  Mazur's theorem
Keywords:  torsion, elliptic curve

Attachments:
Nagell-Lutz theorem (Theorem) by alozano
examples of torsion subgroups of elliptic curves (Example) by alozano
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Cross-references: algorithm, Nagell-Lutz theorem, groups, torsion subgroup, elliptic curve
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This is version 2 of Mazur's theorem on torsion of elliptic curves, born on 2003-08-18, modified 2003-08-18.
Object id is 4607, canonical name is MazursTheoremOnTorsionOfEllipticCurves.
Accessed 4303 times total.

Classification:
AMS MSC14H52 (Algebraic geometry :: Curves :: Elliptic curves)

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