Re: Confused by symbol in equation

From: Randy Poe (poespam-trap_at_yahoo.com)
Date: 08/09/04 

Date: 9 Aug 2004 11:09:35 -0700

"Peter L. Montgomery" <Peter-Lawrence.Montgomery@cwi.nl> wrote in message news:<I2571K.HEA@cwi.nl>...
> In article <a88af92f.0408072032.65279361@posting.google.com>
> dwb1729@yahoo.com (David Bandel) writes:
> >very foolish man you are! a|b means a such that b. or a divides b.
> >anyone who confuses the || <- "or in programming" with | (a single
> >pipeline) must be very very stupid mind like robert israel. (stupid
> >last name. that's a country that jews stole.. they are criminals)
>
> These newsgroups (sci.math and sci.math.symbolic) are not for flames.

Flaming somebody's name is especially idiotic.
>
> While the single vertical line is indeed used for
> "a such that b" and "a divides b", Robert Israel is correct
> that it is also used for bitwise OR in C (different from the
> double vertical line ||, which is used for logical OR in C).

It is also used for logical OR in a number of places.

For instance, Matlab...

 | Logical OR.
    A | B is a matrix whose elements are 1's where either A or B
    has a non-zero element, and 0's where both have zero elements.
    A and B must have the same dimensions unless one is a scalar.

... or the Backus-Naur form for specifying syntaxes (see for example
http://www.augustana.ab.ca/~mohrj/courses/2000.fall/csc370/lecture_notes/ebnf.html)

"Backus-Naur Form (BNF), a metalanguage, gives a formula for
constructing legal strings (but looks like examples of strings)

  Examples:

   <simpleExpr> ::= <term> | <sign><term> | <simpleExpr> <addOp>
<term>

   <addOp> ::= + | - | or

   <unsigned integer> ::= <digit> | <unsigned integer><digit>"

-----------------------------

So Bandel is all wet with his claim that "|" only means "pipeline"
or that logical OR always uses "||", even in programming.

         - Randy

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