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by HuangYuSan
1529 days ago
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I believe in German (possibly also other languages) the thunderbolt ↯ is commonly used to mean "this is a contradiction" in a mathematical proof, equivalently to in English a kind of ⋕ rotated by 45° or the symbol ※.
The symbol ⟂ on the other hand means "false" and is used in particular in formal logic. |
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Yes, we indeed used and afaict still use the thunderbolt for contradiction in my German university.
However "perpendicular" and "bottom/falsum" are two different Unicode codepoints with very similar glyphs.
https://en.m.wikipedia.org/wiki/Up_tack