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Introduction to game dynamics. Pierre Auger IRD UR Geodes, Centre d’île de France et Institut Systèmes Complexes, ENS Lyon. Summary. Hawk-dove game Generalized replicator equations Rock-cissor-paper game Hawk-dove-retaliator and hawk-dove-bully Bi-matrix games.
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Introduction to game dynamics Pierre Auger IRD UR Geodes, Centre d’île de France et Institut Systèmes Complexes, ENS Lyon
Summary • Hawk-dove game • Generalized replicator equations • Rock-cissor-paper game • Hawk-dove-retaliator and hawk-dove-bully • Bi-matrix games
Fighting for resources Dominique Allainé, Lyon 1
Hawk-Dove game • Payoff matrix • Gain • Cost
Playing against a population • Hawk reward • Dove reward • Average reward
Replicator equations With
Replicator equations then Because Leading to
Replicator equations • G<C, dimorphic equilibrium • G>C, pure hawk equilibrium J. Hofbauer & K. Sigmund, 1988 Butterflies
Replicator equations : n tactics (n>2) • Payoff matrix • aij reward when playing i against j
Replicator equations With • Reward player i • Average reward
Equilibrium With • Corner • Unique interior equilibrium (linear)
Rock-Scissor-Paper game • Payoff matrix
Four equilibrium points • Unique interior equilibrium
Local stability analysis saddle • Unique interior equilibrium center
R-C-P phase portrait • First integral
Hawk-Dove-Retaliator game • Payoff matrix
Hawk-Dove-Bully game • Payoff matrix
Bimatrix games (two populations) • Pop 1 against pop 2 • Pop 2 against pop 1
Bimatrix games (2 tactics) • Reward player i • Average reward
Adding any column of constant terms • Pop 1 against pop 2 • Pop 2 against pop 1
Five equilibrium points • Unique interior equilibrium (possibility)
Local stability analysis • Corners (Stable or unstable nodes, saddle) • Unique interior equilibrium (trJ=0 ; center, saddle)
Battle of the sexes • Females : Fast (Fa) or coy (Co) • Males : Faithful (F) or Unfaithful (UF)
Battle of the sexes • Males against females
Battle of the sexes • Females against males
Five equilibrium points • Unique interior equilibrium : C<G<T+C/2
Local stability analysis (center) • Existence of a first integral H(x,y) :