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From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: comp.lang.prolog
Subject: Re: origin of "arity"
Summary: Clipped form of "binary", "ternary" etc.
Message-ID: <1991Jun20.005326.17063@athena.cs.uga.edu>
Date: 20 Jun 91 00:53:26 GMT
References: <3405@shodha.enet.dec.com>
Organization: University of Georgia, Athens
Lines: 31

In article <3405@shodha.enet.dec.com> wahl@shodha.enet.dec.com (David Wahl) writes:
>The word "arity" came up during lunch today in our group and our
>resident mathematician asked whether the word was invented by
>logic programming people or whether it was borrowed from another
>field.  We looked it up in both a standard college English dictionary
>and in a scientific and technical English dictionary and couldn't 
>find the word "arity" in either of them.
>
>Does anyone know where the origin of the word "arity"?
>
  
  Self-evidently, it's a clipped form.

  "binarity"  = "property of being binary (taking 2 arguments)"
  "ternarity" = "property of being ternary (taking 3 arguments)"
  "quaternarity" etc.

  So, "arity" = "property of taking whatever given number of arguments".

It's odd because it is derived from two suffixes with no preceding root.

To find out who first used it, you might try the New Oxford English
Dictionary, which I don't have at hand.



-- 
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Michael A. Covington | Artificial Intelligence Programs
The University of Georgia  |  Athens, GA 30602   U.S.A.
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