why lambda ? 
Author Message
 why lambda ?

There is a question of great importance in our institute: why "lambda"
in "lambda calculus" ? Why not "alpha" or "dzeta" or any other symbol ?
Does anybody know the origin of this choice ? Thank you for you answers.

        Daniel de Rauglaudre
        INRIA - France



Tue, 10 Aug 1993 20:38:57 GMT  
 why lambda ?

Quote:
>There is a question of great importance in our institute: why "lambda"
>in "lambda calculus" ? Why not "alpha" or "dzeta" or any other symbol ?
>Does anybody know the origin of this choice ? Thank you for you answers.

>    Daniel de Rauglaudre
>    INRIA - France


You could ask Church (I think he's still alive) but I don't think that
will help you because the last time they asked him he didn't remember
why he picked lambda.

There are some speculations on lambda being a degenerate form of the
caret-sign (``^'') but I recall Church saying that "it's possible but
I don't know...".  

--Kjell
--
      For athletes and programmers,  ! Kjell E. Post
a woman is the end of their career.  ! CIS/CE
                                     ! University of California, Santa Cruz



Thu, 12 Aug 1993 07:14:52 GMT  
 why lambda ?


writes:

Quote:
|> Rauglaudre) writes:

|> >There is a question of great importance in our institute: why
|> "lambda"
|> >in "lambda calculus" ? Why not "alpha" or "dzeta" or any other
|> symbol ?
|> >Does anybody know the origin of this choice ? Thank you for you
|> answers.
|> >
|> >      Daniel de Rauglaudre
|> >      INRIA - France

|>
|>
|> You could ask Church (I think he's still alive) but I don't think
|> that
|> will help you because the last time they asked him he didn't
|> remember
|> why he picked lambda.
|>
|> There are some speculations on lambda being a degenerate form of the
|> caret-sign (``^'') but I recall Church saying that "it's possible
|> but
|> I don't know...".  

I read somewhere (and I would like to be reminded where) that the origin
is connected with the carat-sign.

In, I think, Whitehead and Russell's Principia Mathematica, the carat is
used to mark each occurance of a bound variable in an expression. Later,
the usage got changed to mark each bound variable once only, by
prefixing the expression with a big caret and the name of the bound
variable.  The big caret is like a capital lambda /\. Later still, (for
printer's convenience?) the lambda became lower case.

--brian

--

Postal: Brian Boutel, Computer Science Dept, Victoria University of Wellington,
        PO Box 600, Wellington, New Zealand
Phone: +64 4 721000



Fri, 13 Aug 1993 08:35:16 GMT  
 why lambda ?

Quote:
>There is a question of great importance in our institute: why "lambda"
>in "lambda calculus" ? Why not "alpha" or "dzeta" or any other symbol ?
>Does anybody know the origin of this choice ? Thank you for you answers.

This seems to be quite easy: lambda just sounds so nice. At least, better
then alpha. Out of concurrence: "dzeta". Just try to think of "omega" -
terrible, and, BTW, preloaded.

Hey, you wont like to make a phonetic, psychologic, historic, what you like,
dissertation on this subject? It might be really appreciated.

Yes, the lambda calculus induces so really deep perception again and
again.

--
Wolfgang Grieskamp



Fri, 13 Aug 1993 10:37:42 GMT  
 why lambda ?
The following I have 'known' for years and years - but I can't remember
who on earth told me. Moreover I have not even checked the reference.
I can't be the only person in the world who believes what follows - if
it's false that will be as interesting to me as it's 'truth' currently is !!!!

.......

In Russell & Whitehead's 'principia' variables which occur in expressions
have a circumflex ^ over them when they appear bound. It seems that at some
point the notation mutated so that the bound variables were introduced with
a larger circumflex - which of course looks like a capital lambda - later a
lower case lambda was used by Church when he developed his calculus.



Sun, 15 Aug 1993 00:21:23 GMT  
 
 [ 5 post ] 

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