Mazur's theorem
Mazur's theorem tells us that the points of finite order on an elliptic curve over the rationals has to have a particular structure. In particular, if Etors is the subgroup of E(Q) of points of finite order then Etors has to have one of the following forms:
1. Zn, a cyclic group of order n where 1≤n≤10 or n = 12
2. Z2 x Z2n, the direct product of a cyclic group of order 2 with one of order 2n for 1≤n≤4
There are examples of curves for each one of these possibilities in Exercise 8.12 on p. 238 of Silverman's The Arithmetic of Elliptic Curves.
I was curious what each of these curves looked like, so I decided to graph both the curves and the points of Etors. Some of the cases were interesting. Others were not.
In any case, here's what I found.





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