This symbol is present in Unicode as the HTML entity ¬, the numeric entity ̤, and the hexadecimal entity ¬.
The late Alonzo Church called it a 'corner', and for mathematical logicians there was and is little appeal from his terminological decisions as the founding and longtime editor of the Journal of Symbolic Logic. Others sometimes call it just a 'not symbol', which is ambiguous because the '~' is also sometimes called a not symbol. The now established Unicode equivalence of '¬ ' and the HTML entity ¬ makes it likely that it will eventually supplant other notation for negation. In the 1950s there was also some use of the name half-turnstile because the assertion symbol '-|' is called a turnstile, but that was too precious to live, and I believe that it has indeed died. John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
