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  "body": "\n## Summary\n\nA Weil divisor on a suitable scheme $X$ is a formal sum with integer coefficients of finitely many closed subvarieties of codimension one.\nThe zeros and poles of a rational function, counted with multiplicity, form a principal Weil divisor.\nThe quotient of all Weil divisors by the principal ones is the divisor class group, which equals the Picard group on smooth varieties.\n\n## Explanations\n\n### L1 human\n\nOn a curve, a divisor is a finite list of points with integer weights, such as $2P - 3Q$.\nOn a surface, the points are replaced by curves, and in general by subvarieties of codimension one.\nA rational function gives a divisor: its zeros with positive weight and its poles with negative weight.\nFor example, on the projective line, the function $x^2/(x - 1)$ has divisor $2[0] - [1] - [\\infty]$.\n",
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