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  "body": "\n## Definition\n\nA [[set|0SJ3RX9TXA]] $A$ is infinite when it is not [[finite|0BBTH3YSZA]], that is, when $A$ is not equinumerous with $\\{1, \\dots, n\\}$ for any natural number $n$.\n\n## Remarks\n\nExamples are $\\mathbb{N}$, $\\mathbb{Z}$, $\\mathbb{Q}$ and $\\mathbb{R}$.\nWith the axiom of choice, a set is infinite exactly when it is equinumerous with a proper subset of itself. This is the Dedekind definition.\nInfinite sets can have different sizes. See [[Cantor's theorem|0WTEMGYV2C]].\n\n## Explanations\n\n### L1 human\n\nAn infinite set never runs out of elements when you count them.\nThe natural numbers are infinite: after each number there is a next one.\n",
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