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Equation 14 · Part 4 · The Type Chart Is a Payoff Matrix, and the Metagame Only Half-Solves It

Symbol x

x˙i=xi(fi(x)−ϕ(x))\dot{x}_i = x_i\big(f_i(x) - \phi(x)\big)
xx

What this part means

x is part of the quantity the equation computes from the expression on the right.

Its job in the formula

x is part of the quantity the equation computes from the expression on the right.

The passage around this formula

Run the continuous replicator equation on the resulting eight-strategy zero-sum game: x˙i\dot{x}_i = xix_i(\big(fi(x)f_i(x) - ϕ(x)\phi(x))\big) , where fi(x)f_i(x) = ∑j\sum_j xjx_j\, U(i,j) is species i ’s expected payoff against the current population mix and ϕ(x)\phi(x) = ∑i\sum_i xix_i fi(x)f_i(x) is the population’s average payoff. Starting from a uniform mix across all eight and integrating to convergence, the system does not settle into anything resembling the real ladder’s spread. It collapses toward a near-monopoly: Great Tusk at 87.71% of the stationary mix, Dragonite at 6.50%, Kingambit at 5.76%, and the other five species asymptoting toward zero, Gholdengo included, despite Gholdengo sitting in second place on the…

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Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

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