Discrete mathematics and graph theory · Maths EE idea · Solid

Colouring graphs to build timetables

A research question to start from

How can graph colouring schedule exams without clashes, and how close does a greedy algorithm come to the minimum number of sessions?

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

Theory (bounds on the chromatic number) and an algorithm evaluated against it.

Mathematics you would need

  • Chromatic number
  • Greedy colouring and ordering
  • Bounds such as Brooks' theorem
  • Worst-case examples

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. Model a timetable you design as a graph.
  2. Prove greedy uses at most Δ + 1 colours.
  3. Find orderings that make greedy do badly and discuss.

Scope and difficulty

Solid. Solid.

Pitfalls

  • Real school data with privacy issues.
  • No proofs of bounds.

Where to start reading

Search a library catalogue or a university's open lecture notes for: greedy colouring bound Delta+1; Welsh-Powell algorithm; Brooks theorem. 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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