Editing Hasse principle (section)

===Quadratic forms===
The [[Hasse–Minkowski theorem]] states that the local–global principle holds for the problem of [[Isotropic quadratic form|representing 0]] by [[quadratic form]]s over the [[rational number]]s (which is [[Hermann Minkowski|Minkowski]]'s result); and more generally over any [[number field]] (as proved by Hasse), when one uses all the appropriate [[local field]] necessary conditions. [[Hasse's theorem on cyclic extensions]] states that the local–global principle applies to the condition of being a relative norm for a [[cyclic extension]] of number fields.