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The "logical negation" sign used to have the vertical line as long as "|", so e.g. "¬A" looked more like "‾|A" but fully vertically aligned with the letter. Sad
by Joker_vD 4y ago
The "logical negation" sign used to have the vertical line as long as "|", so e.g. "¬A" looked more like "‾|A" but fully vertically aligned with the letter. Sadly, this glyph fell out of usage in fonts in favour of "minus with cedilla/descender".
- jjgreen 4y agoI'd always understood it came from Frege's Begriffsschrift, a small descender from a horizontal line (part of a larger diagram), so like a short wide T, then lost its right arm later. Would you have some examples? (a quick google images shows nothing like that ...)
- Joker_vD 4y agoIt was definitely a thing in Soviet works on mathematical/symbolic logic. But here's an example from Curry [0]. As I said, it was mostly a stylistic choice. [0] https://www.google.ru/books/edition/Foundations_of_Mathematical_Logic/27dkTJFrLZIC?hl=ru&gbpv=1&dq=symbolic%20logic&pg=PA4&printsec=frontcover https://www.google.ru/books/edition/Foundations_of_Mathemati...