The Hasse--Minkowski theorem states that if
$$Q(x_1,\ldots,x_n) = \sum_{i,j=1}^n a_{ij} x_ix_j$$ is a quadratic form with $a_{ij} \in \mathbb Z$ and $\det (a_{ij}) \neq 0$, then the equation $$Q(x_1,\ldots,x_n)=0$$ has a nontrivial solution in the integers if and only if it has a solution in the reals and all the $p$-adics.
- Can there be a bounded version to this statement such as if $$Q(x_1,\ldots,x_n) = \sum_{i,j=1}^n a_{ij} x_ix_j$$ is a quadratic form with $a_{ij} \in \mathbb Z$ and $\det (a_{ij}) \neq 0$, then the equation $$Q(x_1,\ldots,x_n)=0$$ has a nontrivial solution in the integers with each coordinate bound in absolute value by $B$ iff $\dots$?
- Can there be a bounded version to at least a linear version of the statement such as if $$L(x_1,\ldots,x_n) = \sum_{i=1}^n a_{i} x_i$$ is a linear form with $a_{i} \in \mathbb Z$ and some criteria, then the equation $$L(x_1,\ldots,x_n)=0$$ has a nontrivial solution in the integers with each coordinate bound in absolute value by $B$ iff $\dots$?