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.ss(lambda,LAMBDA CALCULUS)

	The lambda notation used in LISP was taken from the lambda
calculus described by Alonzo Church in his 1940 book, %2The Calculi
of Lambda Conversion%1.  This section covers some aspects of the
lambda calculus that go beyond what is used in LISP.

	Each LISP expression has a definite %2type%1.  Either it
is like %2qa_x%1 and takes S-expressions as values or it is like
%2λx.[qa_x_._y]%1 and represents a function.  The lambda calculus
doesn't make this distinction, and any expression can be taken as
a function.  This is more general, but a system that realized it
on a computer would most likely do everything in a more complicated
and slower way for the benefit of rarely utilized generality.  We
say "most likely", because someone may invent a way of getting the
generality without paying any operational penalty.

	Lambda calculus is much simpler than LISP in its basic structure,
and its formulas are constructed as follows:

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