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> (C) the thunderbolt ↯ is commonly used for "not" or more specifically for dis-proof in this area Any examples?

by zeteo 5y ago

firstcommentyo 5y ago
High school physics and math as a major. I could scan you my scripts and papers if you're interested.....no won't. ;-D But maybe "commonly used" was maybe the wrong term. More appropriately: "sometimes" or "by some".
- IshKebab 5y ago
  I have never seen it used as not once in maths or physics. "extremely rarely" perhaps.
  - mywittyname 5y ago
    To be fair, there are lot of math symbols out there. http://mirrors.dotsrc.org/ctan/info/symbols/comprehensive/symbols-a4.pdf http://mirrors.dotsrc.org/ctan/info/symbols/comprehensive/sy... There are lots of examples of the lightning bolt in there. In fact, under ulsy Contradiction symbols, there are four variants. I also noticed the exact symbol being discussed is listed under "Angles".
- renewiltord 5y ago
  Where in the world? I’ve never used it despite similar background. Perhaps regional?
HuangYuSan 5y ago
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.
- froh 5y ago
  Yes and no. 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 https://en.m.wikipedia.org/wiki/Up_tack
contravariant 5y ago
I've seen it used for contradiction. Though that's not the same thing as 'not' and I can't think of why you'd combine this with orthogonality.
hedora 5y ago
If the thunderbolt means not, and the right angle is displaying the x and y axis, then this symbol could be a pun for "not a function".

> (C) the thunderbolt ↯ is commonly used for "not" or more specifically for dis-proof in this area Any examples?

by zeteo 5y ago

> (C) the thunderbolt ↯ is commonly used for "not" or more specifically for dis-proof in this area Any examples?

High school physics and math as a major. I could scan you my scripts and papers if you're interested.....no won't. ;-D But maybe "commonly used" was maybe the wrong term. More appropriately: "sometimes" or "by some".

IshKebab 5y ago
I have never seen it used as not once in maths or physics. "extremely rarely" perhaps.
- mywittyname 5y ago
  To be fair, there are lot of math symbols out there. http://mirrors.dotsrc.org/ctan/info/symbols/comprehensive/symbols-a4.pdf http://mirrors.dotsrc.org/ctan/info/symbols/comprehensive/sy... There are lots of examples of the lightning bolt in there. In fact, under ulsy Contradiction symbols, there are four variants. I also noticed the exact symbol being discussed is listed under "Angles".
renewiltord 5y ago
Where in the world? I’ve never used it despite similar background. Perhaps regional?

HuangYuSan 5y ago

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.

froh 5y ago
Yes and no. 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 https://en.m.wikipedia.org/wiki/Up_tack

contravariant 5y ago

I've seen it used for contradiction. Though that's not the same thing as 'not' and I can't think of why you'd combine this with orthogonality.

hedora 5y ago

If the thunderbolt means not, and the right angle is displaying the x and y axis, then this symbol could be a pun for "not a function".