ball-bearing mousetrap

James A. Landau JJJRLandau at AOL.COM
Wed Mar 21 16:17:08 UTC 2001


In a message dated 3/21/01 10:16:41 AM Eastern Standard Time, gt1 at NYU.EDU
writes:

<< Just one example: "ball-bearing mousetrap: a
 tomcat".  (This one I am told was invented by a science fiction writer
 named George O. Smith for the purpose of sneaking something off-color
 past a notoriously puritanical editor named Kay Tarrant (assistant
 editor for many years of Astounding Science Fiction (later renamed
 Analog))).

 First, let us all admire quietly the nested ((())). >>

Us (we?) computer programmers are used to multiple levels of parentheses,
known in the trade as "nested parentheses".    For example, the name of the
popular computer language LISP is alleged to be an acronym for "Lots of
Idiotic, Stupid Parentheses".

There is a technique for eliminating parentheses entirely.  It is known as

<quote>
Polish notation [which] was described in the 1920s by Polish mathematician
Jan Lukasiewicz as a logical system for the specification of mathematical
equations without parentheses. There are two versions, prefix notation and
postfix notation. In prefix notation, the operators are placed before the
operand. In postfix notation, this order is reversed. The following example
illustrates the two. The asterisk is used for the multiplication sign.

   Equation with parenthesis       (1 + 2) * 3
   Prefix notation                 * 3 + 1 2       or      * + 1 2 3
   Postfix notation                1 2 + 3 *       or      3 1 2 + *

Postfix notation has since become known as reverse Polish notation.

<end quote>
quoted from http://users.ece.gatech.edu/~mleach/revpol/

Are you with me so far?











If you answered yes, then I have succeeded in pulling your leg, because
Lukasiewicz "Polish" notation applies only to algebra, not to natural
language text.  Or in other words, you have fallen for a politically-correct
Polish joke!


Seriously, I heard the "ball-bearing mousetrap" story in college in the late
1960's.  The story may be garbled or apochryphal, and even if accurate, I was
not told whether Smith invented the expression or merely used a risque phrase
he had heard from someone else.

           - Jim Landau



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