# ¬?



## chris_&#3617;&#3623;&#3618;&#3652;&#3607;&#3618; (Jan 14, 2007)

hi , i know nothing about computers so i was just wondering what ¬ is lol


thanks,

chris


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## exile (Jan 14, 2007)

chris_?????? said:


> hi , i know nothing about computers so i was just wondering what ¬ is lol
> 
> 
> thanks,
> ...



In formal logic it's the negation connective: if X is true, then ¬X is false, if X is false then ¬X is true. Not sure how it's used as part of code, though. It would part of the semantics for a higher-order language like Lisp or Prolog, no?


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## ed-swckf (Jan 14, 2007)

chris_&#3617;&#3623;&#3618;&#3652;&#3607;&#3618;;700086 said:
			
		

> hi , i know nothing about computers so i was just wondering what ¬ is lol
> 
> 
> thanks,
> ...


 

Thats a not sign, a logical not sign you can also use a tilde ~ or a caret ^ as a logical not and in programming you will probably also us a exclamation ! as a not although in logical maths that tends to mean unique as opposed to not.  So basically ¬A  means not A, simple really!


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## arnisador (Jan 14, 2007)

Was it used in APL? I can no longer remember.

Hmmm, looks like rotated versions were at least: APL keyboard.


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## mrhnau (Jan 14, 2007)

arnisador said:


> Was it used in APL? I can no longer remember.
> 
> Hmmm, looks like rotated versions were at least: APL keyboard.



Looks like it...

personally, I've used it to make text boxes  Never really did logic w/ a keyboard before. I took it back in the stone ages when we actually had to use pencils and pens!


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## CoryKS (Jan 14, 2007)

I run across it every once in a while in old COBOL programs; the compiler interprets it as a NOT.  It's fallen out of favor in our shop, probably because nobody can remember the key sequence used to enter it.


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## FearlessFreep (Jan 14, 2007)

I run into that with Smalltalk as well.  The original Smalltlak used an 'up arrow' for 'return' and a 'right arrow' for assignment.  Squeak still recognizes it.

However, most versions just use ^ for 'return' and := for assignment.


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## crushing (Jan 14, 2007)

chris_&#3617;&#3623;&#3618;&#3652;&#3607;&#3618;;700086 said:
			
		

> hi , i know nothing about computers so i was just wondering what ¬ is lol
> 
> 
> thanks,
> ...


 
It's what I get when I hold the ALT key and press 170.

Here is Alt-169 &#8976;

&#9617;&#9617;&#9617;&#9617;&#9618;&#9618;&#9618;&#9618;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9618;&#9618;&#9618;&#9618;&#9617;&#9617;&#9617;&#9617;


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## exile (Jan 14, 2007)

mrhnau said:


> Looks like it...
> 
> personally, I've used it to make text boxes  Never really did logic w/ a keyboard before. I took it back in the stone ages when we actually had to use pencils and pens!



If you ever need to, run LaTeXit's a math typesetting program that runs on unix/linux and yield production quality output (actually, a lot of math/physics/logic textbooks and monographs are produced in LaTeX). It makes the yield of standard equation editors looks like something someone scratched in the groud with a stick...


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## arnisador (Jan 15, 2007)

TeX is essential; I use Scientific Workplace for it. I wrote my entire numerical analysis textbook in it.


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## exile (Jan 15, 2007)

arnisador said:


> TeX is essential; I use Scientific Workplace for it. I wrote my entire numerical analysis textbook in it.



Aha, another TeXie! It's great, isn't itas long as you don't bugger up some delimiter pairing, in which case it can take you (or at least me) an hour to two to find what went wrong... which do you use, raw TeX, or LaTeX, Leslie Lamport's macro package for TeX? And alsoyou have a numerical analysis textbook out? Coolcan I ask who published it, and did they use your TeX file right off the shelf to do production (as they should have been able to do, if they've got the right apporach to technical publishing)?


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## ed-swckf (Jan 17, 2007)

crushing said:


> It's what I get when I hold the ALT key and press 170.
> 
> Here is Alt-169 &#8976;
> 
> &#9617;&#9617;&#9617;&#9617;&#9618;&#9618;&#9618;&#9618;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9619;&#9618;&#9618;&#9618;&#9618;&#9617;&#9617;&#9617;&#9617;


 
¬&#8976;-&#9688;&#9675;&#9824;&#9786;&#9787;&#9827;&#9830;&#9787;&#9827;MXc&#8993;~{&#8962;ô&#8359;£&#8359;&#9835;&#9576;&#9560;|&#9835;æÜ|É~&#9567;ûCy4&#9565;&#9830;441  woohoo&#8993;&#9787; &#9632;²&#934;&#8730;&#9573;&#8993;&#966;&#8745;&#8735;&#8596;&#8735;&#8596;"$&''&#9660; &#9650;-.&#964;0&#9571;&#9824;7CÄ>DJNUce&#9567;Ü


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