Skip to main content
deleted 1 character in body
Source Link

I'm not sure whether this is obvious or not. If I remember correctly, theThe curve $X(1)$ parametrices all elliptic curves up to isomorphism class over $\mathbb{ C}$, and a $K$-rational point corresponds to an elliptic curve whose $j$-invariant lies in $K$, andbut if I remember correctly the $K$-rational points actually classify elliptic curves up to isomorphism over $K$. Is there an obvious reason for this?

I'm not sure whether this is obvious or not. If I remember correctly, the curve $X(1)$ parametrices all elliptic curves up to isomorphism class over $\mathbb{ C}$, and a $K$-rational point corresponds to an elliptic curve whose $j$-invariant lies in $K$, and the $K$-rational points actually classify elliptic curves up to isomorphism over $K$. Is there an obvious reason for this?

I'm not sure whether this is obvious or not. The curve $X(1)$ parametrices all elliptic curves up to isomorphism class over $\mathbb{ C}$, and a $K$-rational point corresponds to an elliptic curve whose $j$-invariant lies in $K$, but if I remember correctly the $K$-rational points actually classify elliptic curves up to isomorphism over $K$. Is there an obvious reason for this?

Source Link

Do rational points on $X(1)$ correspond to elliptic curves up to rational isomorphism?

I'm not sure whether this is obvious or not. If I remember correctly, the curve $X(1)$ parametrices all elliptic curves up to isomorphism class over $\mathbb{ C}$, and a $K$-rational point corresponds to an elliptic curve whose $j$-invariant lies in $K$, and the $K$-rational points actually classify elliptic curves up to isomorphism over $K$. Is there an obvious reason for this?