Equivalence classes of Niho bent functions are in one-to-one correspondence with equivalence classes of ovals in a projective plane. Since a hyperoval can produce several ovals, each hyperoval is associated with several inequivalent Niho bent functions. For all known types of hyperovals we described the equivalence classes of the corresponding Niho bent functions. For some types of hyperovals the number of equivalence classes of the associated Niho bent functions are at most 4. In general, the number of equivalence classes of associated Niho bent functions increases exponentially as the dimension of the underlying vector space grows. In small dimensions the equivalence classes were considered in detail.

Niho弯曲函数的等价类与投影平面中椭圆的等价类一一对应。由于一个超卵形体可以产生多个椭圆形，因此每个超卵形体都具有多个不等价的Niho弯曲功能。对于所有已知类型的超卵形，我们描述了相应的Niho弯曲函数的等价类。对于某些类型的超椭圆形，与之相关的Niho弯曲函数的等价类数最多为4。通常，与之相关的Niho弯曲函数的等价类数随着底层向量空间维数的增长呈指数增长。在小尺寸中，详细考虑了等效类。