[plt-scheme] Why "lambda"?

From: Prabhakar Ragde (plragde at uwaterloo.ca)
Date: Tue May 26 12:38:58 EDT 2009

Dave Herman wrote:

>> Does anyone know if Church had anything in mind for lambda to stand
>> > for, or was it just an arbitrary choice?
> page 7:
> http://www-maths.swan.ac.uk/staff/jrh/papers/JRHHislamWeb.pdf
> page 182:
> http://citeseerx.ist.psu.edu/viewdoc/summary?doi=

 From the second reference:

> Church originally intended to use the notation xˆ .2x+1. The typesetter could
> not position the hat on top of the x

This I do not believe. A typesetter for a journal of mathematics in the 
1930's could not typeset x^? (Heh, Thunderbird appears unable to. Let's 
try again: ˆx.)

What I read somewhere (I cannot find it at this moment) was that the hat 
was moved to before the x (as the first reference above confirms, to 
distinguish function-abstraction from class-abstraction), but that it 
was then made larger for visibility, using an upper-case lambda, which 
looks like an upside-down V. But that looked too much like a capital A, 
so they went with lower-case lambda. --PR

Posted on the users mailing list.