Proportionality Symbol

Date: 05/20/2003 at 04:03:38
From: Lauren
Subject: Rates and variation symbol

Do you know the name of the little symbol used in the topic of rates 
and variation that means "in proportion to"? It looks a bit like 
alpha, only more (this sounds odd, but it's the best way to describe 
it) "fish-like."

Date: 05/20/2003 at 12:06:00
From: Doctor Peterson
Subject: Re: Rates and variation symbol

Hi, Lauren.

Many symbols have no specific name, and are just referred to by their 
usage; this can be called the proportionality symbol. In fact, the 
'official' name of the symbol in Unicode (a set of international 
characters for computers) is "proportional to":

   Symbol Characters and Glyphs - W3C Working Draft
   http://www.w3.org/Math/characters/html/symbol.html 

Looking for a mention of an actual name, I looked up its history in 
Jeff Miller's:

   Earliest Uses of Symbols of Relation
   http://jeff560.tripod.com/relation.html 

It is just called "The symbol for variation (an eight lying on its 
side with a piece removed)."

Eric Weisstein's World of Mathematics gives no name:

   Proportional
   http://mathworld.wolfram.com/Proportional.html 

If you prefer to describe it by its appearance rather than strictly by 
its usage, you might call it an "open alpha" or "loose alpha," rather 
than "fishy alpha." People do often describe it (wrongly) as an alpha, 
but I haven't seen these modifiers used anywhere.

If you have any further questions, feel free to write back.

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/