Neliöresidujen
Neliöresidujen, also known as quadratic residues, are a fundamental concept in number theory. An integer a is a quadratic residue modulo n if there exists an integer x such that x^2 is congruent to a modulo n. In simpler terms, a is a quadratic residue modulo n if it is the remainder when a perfect square is divided by n. If no such integer x exists, then a is called a quadratic non-residue modulo n.
The study of quadratic residues is primarily concerned with determining whether a given integer is a quadratic
The concept extends to composite moduli, although the analysis becomes more complex, often involving the Chinese