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Topic summary · Student revision

Matchings Topic Review summary

Self-review on bipartite matchings, alternating paths, and the maximum matching algorithm.

Files: Topic-Review-Matchings.pdf · Topic-Review-Matchings-Answers.pdf · free public downloads · diagrams in the PDFs

Key learning points

  • Bipartite graph: vertices split into two sets with edges only between sets.
  • A matching pairs vertices with no shared endpoint.
  • Alternating / augmenting paths improve a matching.
  • Apply the maximum matching algorithm systematically from an incomplete matching.
  • State the final matching as explicit pairs.

Worked example 1 — Augment

What does an augmenting path do?

Working

Increasesmatchingsizeby1Increases matching size by 1

Flip matched/unmatched edges along the path.

Worked example 2 — Complete

When is a matching complete?

Working

EveryvertexofthesmallersetismatchedEvery vertex of the smaller set is matched

Also called a perfect matching when both sets equal.

Worked example 3 — Practice point 1

Apply this idea from the Topic Review: Bipartite graph: vertices split into two sets with edges only between sets.

Working

see answers PDF\text{see answers PDF}

Attempt without notes, then check the answers PDF.

Worked example 4 — Practice point 2

Apply this idea from the Topic Review: A matching pairs vertices with no shared endpoint.

Working

see answers PDF\text{see answers PDF}

Attempt without notes, then check the answers PDF.

Scaffolded Learning Sheet and answers (PDFs)

This page is a short, searchable overview for revision and search engines. Use the Scaffolded Learning Sheet first, then the Answers PDF for a full written solution. The printable PDFs remain the main classroom resource.