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  "body": "\n## Definition\n\nLet $R$ be a [[binary relation|08EJC6Q25H]] on a set $A$.\nThe relation $R$ is symmetric when, for all $a, b \\in A$, $a \\mathrel{R} b$ implies $b \\mathrel{R} a$.\n\n## Remarks\n\nEquality is symmetric. The relation $\\le$ on $\\mathbb{R}$ is not symmetric, because $1 \\le 2$ but not $2 \\le 1$.\nA relation $R$ is symmetric exactly when it is equal to its [[converse|0JCSQNNP2M]].\n\n## Explanations\n\n### L1 human\n\n\"Is a sibling of\" is symmetric: if Ann is a sibling of Bob, then Bob is a sibling of Ann.\n\"Is a parent of\" is not symmetric.\n",
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