Theory of numbers: Quadratic residues @richarde.borcherds7998

Uploaded February 2021 | Updated September 2026, 2 weeks ago

This lecture is part of an online undergraduate course on the theory of numbers.

We define quadratic residues (squares) and describe their basic properties, in particular Euler's criterion. The we describe fast algorithms to test whether a number is a quadratic residue, and if so to find its square root.

For the other lectures in the course see youtube.com/playlist?list=PL8yHsr3EFj52Qf7lc3HHvHRdIysxEcj1H

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Theory of numbers: Congruences: Primitive roots

Introduction to number theory lecture 34. Gauss sums

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Introduction to number theory lecture 27. Groups and number theory

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