Game Theory vs DecisionPlay

Learn game theory and solve games step by step — with exact fractions, not rounded decimals. Game Theory: Nash Equilibrium is a course, a solver and a problem set in one app. Every answer comes with the reasoning behind it, so you can check your homework, prepare for an exam, or simply understand why people cooperate, compete and bluff. SOLVER — FOUR KINDS OF GAMES • Matrix games: 2 players with up to 6 strategies each, or 3 players with up to 3. Dominant strategies, iterated elimination, rationalizability, pure and mixed Nash equilibria, refinements, equilibrium selection, maximin, Pareto efficiency, Nash bargaining, Stackelberg commitment, repeated games, evolutionarily stable strategies and correlated equilibrium — 14 concepts in total. • Game trees: build a sequential game, add moves of chance, and solve it by backward induction. See which Nash equilibria rest on threats nobody would carry out. • Bayesian games: give one or both players private types and find the pure and mixed Bayesian Nash equilibria, checked type by type. • Cournot markets: 2 to 5 firms with known or private costs. Get best responses, the equilibrium, price, profits and consumer surplus, compared with a cartel, a Stackelberg leader and perfect competition — with the reaction curves drawn. LEARN — 24 TOPICS IN 6 UNITS From normal-form games and dominant strategies to mixed equilibria, subgame perfection, information sets, Bayesian games, signaling, auctions and continuous strategies. Each topic builds on the one before and includes a worked example computed by the same engine as the solver. PRACTICE — 31 CLASSIC PROBLEMS The Prisoner's Dilemma, Battle of the Sexes, Stag Hunt, Chicken, the tragedy of the commons, auctions, the Traveller's Dilemma and many more. Pick the equilibria yourself, get instant feedback, then study the full solution. WHY STUDENTS USE IT • Exact results: fractions such as 2/3 instead of 0.667, and all equilibria of two-player games, not just one. • Step by step: the method is shown, not only the answer. • 10 languages: English, Turkish, German, Spanish, French, Italian, Portuguese, Russian, Chinese and Japanese. • Lessons, solver and practice work offline (watching an ad needs a connection). No account, no banners. FREE TO TRY, ONE PURCHASE FOR EVERYTHING Lessons 1, 2 and 24 and two practice problems (the Prisoner's Dilemma and Chicken, with their solutions) are free, and so is the solver: without Full Access, each solve is unlocked by one short ad that you choose to watch. Full Access — a one-time in-app purchase, not a subscription — unlocks every lesson, ad-free solving and all 31 problems with their solutions. Made for students of economics, business, computer science and political science, in high school and at university, and for anyone curious about strategic thinking.

Game theory made easy. DecisionPlay turns everyday conflicts into strategy puzzles. Every situation, from splitting a dinner bill to a holdout negotiation, hides a game with rules. Name the game, see what each side wants, and find the move that changes the outcome. PLAY THE DAILY PUZZLE A new situation every day. Guess which game is hiding inside it in three tries, then read the full breakdown. Keep your streak going and share your result without spoilers. SCENARIOS TO PLAY Dating, family, work, negotiation, history, policy and more. Make the calls, then see how a game theorist reads the same moments. MAP YOUR OWN SITUATION Describe a real decision in plain words. DecisionPlay names the players, the options and the pressure points, and shows which assumptions drive the result. LEARN BY PLAYING Prisoner's Dilemma, Chicken, Stag Hunt, signaling and more, explained with plain language and interactive demos. Play bots that each follow one rule and beat them. NO ACCOUNT NEEDED Everything works without signing in. Your progress stays on your device. Move your streak to a new phone with a short code. Educational, not advice.