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  "body": "\n## Definition\n\nLet $f \\colon A \\to B$ be a [[function|0XHDTE5YMZ]].\nThe domain of $f$ is the set $A$.\n\n## Remarks\n\nThe function $f$ has a value $f(a)$ for each $a$ in its domain.\nIn calculus, the natural domain of a formula is the largest set of real numbers where the formula has a meaning. For $1/x$, it is $\\mathbb{R} \\setminus \\{0\\}$.\n\n## Explanations\n\n### L1 human\n\nThe domain says which inputs are allowed.\nFor the square root as a real function, the domain is the set of real numbers $x \\ge 0$.\n",
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