2018-12-04

Factoring 21 with Shor's algorithm: qubits, periods, and retries

Follow a normalized order-finding example, understand Fourier interference and its limits, and see why base five fails before base two yields the factors three and seven.

2018-10-05

Which primes have the form a squared + ab + b squared?

Prove the prime representation criterion using Eisenstein integers, polynomial quotients over finite fields, Euclidean division, and norms.