Solution
= Solution
The <Theorem of the square> says that for an <abelian variety> $X$, a <line bundle> $L$, and $x,y\in X(k)$,
$$
\boxed{T_{x+y}^*L\otimes L\simeq T_x^*L\otimes T_y^*L,}
$$
where $T_x$ denotes translation by $x$.
= Solution
The <Theorem of the square> says that for an <abelian variety> $X$, a <line bundle> $L$, and $x,y\in X(k)$,
$$
\boxed{T_{x+y}^*L\otimes L\simeq T_x^*L\otimes T_y^*L,}
$$
where $T_x$ denotes translation by $x$.