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Topic summary · Student revision

Game Theory Topic Review summary

Self-review on zero-sum games, play-safe strategies, and mixed-strategy equilibria for 2imes22 imes2 games.

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

Key learning points

  • Pay-off matrix from the row player’s viewpoint (usually).
  • Play-safe: maximin for rows, minimax for columns.
  • Saddle point: entry that is both maximin and minimax — stable pure strategy.
  • No saddle ⇒ mixed strategies; solve for probabilities making opponent indifferent.
  • Value of the game is the expected pay-off under optimal mixed strategies.

Worked example 1 — Saddle

What is a saddle point?

Working

Entrythatisminofitsrowandmaxofitscolumn(orviceversaperconvention)Entry that is min of its row and max of its column (or vice versa per convention)

Stable pure-strategy solution.

Worked example 2 — Mixed

Idea of mixed strategy in 2×2.

Working

Chooserowswithprobabilitiesp,1−ptoequalisecolumnexpectedvaluesChoose rows with probabilities p,1−p to equalise column expected values

Then solve for p.

Worked example 3 — Practice point 1

Apply this idea from the Topic Review: Pay-off matrix from the row player’s viewpoint (usually).

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: Play-safe: maximin for rows, minimax for columns.

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.

Game Theory Topic Review summary — worksheet & answers PDF