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  "body": "\n## Statement\n\nThe set $\\mathbb{Z}$ of integers is [[countably infinite|0SEZ3JGZP7]].\nThe function $f \\colon \\mathbb{N} \\to \\mathbb{Z}$ with $f(2k) = k$ and $f(2k + 1) = -(k + 1)$ is a [[bijection|0SNQEF7Z53]].\n\n## Remarks\n\nThe bijection lists the integers as $0, -1, 1, -2, 2, \\dots$.\nSo $|\\mathbb{Z}| = |\\mathbb{N}| = \\aleph_0$, although $\\mathbb{N}$ is a proper subset of $\\mathbb{Z}$.\n\n## Explanations\n\n### L1 human\n\nThe list $0, 1, 2, \\dots$ never reaches the negative integers.\nAlternate between the two signs, and every integer gets a position in the list.\n",
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