Re: \neg

Donald Arseneau wrote: 
David DeVidi <ddevidi@xxxxxxxxxxxxxxxxxxxx> writes:


What year are we talking about here?  I would have thought that the story
of tilde as negation must go back further than this, and probably had
something to do with what symbols were available on Bertrand Russell's
typewriter or something.



Probably true. I guess the character set mapping goes back to
before computers, and the tradition carried on.

(Part of the legacy is typing logical-not as the non-breaking
space for Tex on an Amdahl computer.)




The rotated L symbol appeared on the IBM 026 and 029 keypunches that were widely used in computer centers in the 1960s and 1970s. The symbol is used in IBM's PL/I programming language to indicate bit-wise negation and is used as a prefix to >, <, and = to indicate not greater than, not less than, and not equal to, respectively.

Charles B. Cameron
.

Relevant Pages

  • Re: eg
    ... A tilde should mean "approximate", ... > two character sets, they decided to map between those two vaguely ... of tilde as negation must go back further than this, ... Many introductory books still do use that horrible notation ...
    (comp.text.tex)
  • Re: removing zeros from a vector
    ... Jeremy Smith wrote: ... What is the double tilde for in the following statement? ... It's a matlab trick to get a logical vector with trues when A is not ...
    (comp.soft-sys.matlab)
  • Re: reductio ad falsum versus reductio ad absurdum
    ... constructive reductio ADDS a tilde, ... DN (double negation). ... Prev by Date: ...
    (sci.logic)
  • Re: How to use xspace followed by no-op command?
    ... Donald Arseneau wrote: ... The negation gives a negative number and the \romannumeral of a negative number is null. ... (I "discovered" this trick some years ago, but have seen other people discover it also, and have no idea who discovered it first -- probably ... someone doing the initial work on TeX.) ...
    (comp.text.tex)
Loading