Economics

The registered models of skcomplex.models.economics. The page of each shows its factory, its component types with their states, parameters, and laws as written, and, for the forms that have them, its equations as SymbolicAnalysis returns them, so it serves as the pattern for a model of your own.

Econophysics

• Boltzmann wealth exchange: A Boltzmann wealth exchange model where every agent starts with one unit.
• El Farol: Arthur's El Farol bar problem, whose attendance self-organizes around the capacity.
• Exchange with debt limit and with saving propensity: A kinetic wealth exchange model with a saving propensity or a debt limit.
• Kinetic wealth and welfare dynamics: The kinetic theory of wealth classes, with a welfare policy when the tax is positive.
• Kolkata Paise Restaurant: The Kolkata Paise Restaurant problem, where diners spread over restaurants that serve one meal each.
• Minority game and its evolutionary version: The minority game of an odd number of agents with two random strategies each.

Finance

• Bouchaud-Mézard wealth: Bouchaud and Mezard's wealth dynamics, random multiplicative returns with exchange between neighbours.
• Correlated geometric Brownian motions: Two assets whose prices follow geometric Brownian motions driven by correlated Wiener processes.
• DebtRank cascades: The DebtRank cascade of distress from a set of banks through their interbank loans.
• Geometric Brownian motion: An asset whose price follows geometric Brownian motion.
• Gibrat: Firms that grow by Gibrat's law of proportionate effect, which makes their sizes lognormal.
• Kesten processes: Firms whose sizes follow Kesten's process, a random multiplicative factor plus a random positive term.
• Multiplicative: Levy and Solomon's multiplicative process, whose floor at a fraction of the mean makes a power-law tail.
• Order book with imitation: A stock market of fundamentalists and chartists on a grid who trade in a limit order book and imitate.
• Random-walk traders with arbitrage: Schwichtenberg's diffusion of a good by random-walk traders, minimally coupled to exchange rates.

Innovation

• Arthur-Polak technology evolution: Arthur and Polak's evolution of technology, which builds logic functions from NAND gates.
• Bass diffusion: The Bass diffusion model, people who adopt a new product through advertising and word of mouth.
• Combinatorial creative phase transition: The diversity of a combinatorial system, which jumps from sparse to full above a critical rule density.
• Fixed-line phone adoption: Hamill and Gilbert's adoption of fixed-line phones by British households from 1951.
• NK technology model: McNerney's model of technological improvement, whose cost falls as a power of the cumulative production.

Macroeconomics

• Capital stock: Meadows' capital stock, grown by reinvested output and drained by depreciation.
• Exchange rates in international trade: Hamill and Gilbert's staged adjustment of trade and the exchange rate to a rise in home prices.
• Firm and bank credit networks: A credit market where firms sample banks and switch to cheaper lenders, and defaults hit the lenders.
• Fractional-reserve banking: Customers and banks whose lending of excess reserves multiplies the base money by 1 / ratio.
• Metaphoria mortal hunter-gatherer and monetary economies: Gooding's Metaphoria, a mortal population of hunter-gatherers or of a monetary economy.
• Multiplier-accelerator: Samuelson's multiplier-accelerator, Y_{t+1} = c (1 + v) Y_t - c v Y_{t-1} + G.
• Pontryagin capital and consumption: The Ramsey economy that chooses the consumption path maximising its discounted utility.
• Solow: An economy whose capital per worker approaches its steady state through saving and depreciation.
• Stock-flow consistent monetary economy: A stock-flow consistent economy, a closed circuit of money between households, firms, and a bank.
• Toy firm investment: Heterogeneous firms that invest out of past profits and sell at random prices, with entry and exit.

Markets

• Ajani's choice and fair food: Chesney's choice between fair-trade and regular food of consumers who influence their neighbours.
• Beer distribution game: Sterman's beer distribution game, a supply chain whose orders swing wider at every echelon upstream.
• Bilateral two-good trade on complete, isolated, and small-world networks: Wilhite's bilateral barter of two goods among traders on one of four trade networks.
• Brock-Hommes heuristic switching: Brock and Hommes' asset market with traders switching between fundamentalists and trend chasers.
• Car wash queue: Chesney's Clean and Wax hand car wash, a shadow account of the revenue of its workers' labour.
• Car-dealer inventory with delays: Meadows' car dealership, whose inventory oscillates after a step in demand because of its delays.
• Cobweb: A market whose price converges to or oscillates around equilibrium as supply lags the price.
• Commodity cycle with capacity delay: A commodity market whose price and capacity cycle because new capacity arrives after a delay.
• Cournot duopoly with beliefs: Two Cournot duopolists that adjust their output to their beliefs about each other.
• Customers choosing between two shops of perishable goods: Customers who choose between two shops of perishable goods, preferring the one that sold fresher goods.
• Double auction: Gode and Sunder's double auction of zero-intelligence traders, a step per trading period.
• Edgeworth and Red Cross barter: Barter of chocolate and cigarettes, in an Edgeworth box of two barterers or among many prisoners.
• Labour market: Hamill and Gilbert's labour market of firms posting wage offers and unemployed workers searching.
• Produce market: Hamill and Gilbert's produce market, where shoppers with lists of produce visit stalls at random.
• Riccati price adjustment: A price that moves with excess demand under linear demand and saturating quadratic supply.
• Shops and digital markets: Shops on a grid that compete for the shoppers on every cell, in person or in a digital market.
• Static oligopoly equilibria: The equilibria of a Cournot duopoly and of a pricing game of firms with loyal customers and switchers.
• Sugarscape: The Sugarscape of Epstein and Axtell, foragers of random vision and metabolism on two sugar peaks.
• Toy and three-goods traders: Traders who wander a grid and barter two or three goods with their neighbours.

Resources

• Cocoa: A cocoa production system, plantations that boom with their profit and bust with the insects they invite.
• Food security models: A food security system, the rice self-sufficiency of a country under subsidy, research, and extension.
• Harvesting farmers: A socio-ecological model of farmer agents harvesting a logistically regrowing resource.
• Hilsa fishery: A hilsa fishery, the life cycle of a migratory fish that the catch of juveniles and spawners depletes.
• Oil economy: Meadows' oil economy, capital that grows on a nonrenewable resource and collapses as it runs out.
• Optimal harvesting: A logistic resource harvested with the effort that maximises its discounted profit.
• Renewable fishery with capital: Meadows' fishing fleet, capital that grows on a renewable resource and can overshoot it.
• Tragedy of the meadow commons: Herders whose cows graze a shared meadow, each adding cows while a cow pays, until the grass collapses.
• Von Thünen land use: A square plain around one market at its centre, whose every cell grows the crop of highest bid rent.