Number theory · Maths EE idea · Accessible

The Chinese remainder theorem and calendar cycles

A research question to start from

How does the Chinese remainder theorem explain when calendar cycles of different lengths coincide, and how can solutions be constructed efficiently?

A starting point, not your question: change the case, the comparison or the limit until it is yours. The research-question builder helps you check it.

Why it works as a maths EE

A theorem with a constructive proof that you can apply to a context you choose, and an algorithm to evaluate.

Mathematics you would need

  • Linear congruences
  • The Euclidean algorithm and Bézout's identity
  • The Chinese remainder theorem

Much of this goes beyond the DP course. That is expected in a maths EE, but you must understand and explain everything you use.

One possible line of attack

  1. Prove the theorem and turn the proof into a construction.
  2. Apply it to cycles you choose (for example, weekly and lunar-style cycles, or planetary alignments with idealised periods).
  3. Handle moduli that are not coprime and say when there is no solution.

Scope and difficulty

Accessible. Accessible; make sure the context does not take over.

Pitfalls

  • Context-heavy essay with thin mathematics.
  • Assuming coprime moduli everywhere.

Where to start reading

Search a library catalogue or a university's open lecture notes for: Chinese remainder theorem constructive proof; Bezout identity. Prefer textbooks, lecture notes and journal articles to a single website, and cite everything you use (how to reference a maths EE).

Make it your EE

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