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  "body": "\n## Summary\n\nA copula is a joint [[cumulative distribution function|0H8H7ZTHW2]] on the unit cube whose one-dimensional [[marginals|0MXT6PRZZ6]] are uniform on $[0, 1]$.\nBy [[Sklar's theorem|ZD7V7R27R9]], every joint distribution splits into its marginal distributions and a copula that carries the dependence between the coordinates.\nCopulas let one model the marginals and the dependence separately.\nThey are used in finance, insurance and hydrology.\n\n## Explanations\n\n### L1 human\n\nTwo quantities, like the rainfall in two nearby towns, each have their own distribution, and they also influence each other.\nA copula describes only the way they influence each other, after each one is rescaled to a number between $0$ and $1$ by its own distribution.\nThe independence copula $C(u, v) = u v$ says there is no influence at all.\nThe copula $C(u, v) = \\min(u, v)$ says that both quantities always move in perfect step.\n",
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