[1] : WordNet (r) 2.0

idempotent
     adj : unchanged in value following multiplication by itself; "this
           matrix is idempotent"

[2] : Jargon File (4.3.1, 29 Jun 2001)

idempotent adj. from mathematical techspeak acting as if used only
   once, even if used multiple times. this term is often used with respect
   to c header files, which contain common definitions and declarations
   to be included by several source files. if a header file is ever
   included twice during the same compilation perhaps due to nested
   include files, compilation errors can result unless the header file
   has protected itself against multiple inclusion; a header file so
   protected is said to be idempotent. the term can also be used to
   describe an initialization subroutine that is arranged to perform some
   critical action exactly once, even if the routine is called several
   times.


see also:
c 

[3] : The Free On-line Dictionary of Computing (27 SEP 03)

idempotent
     
        1. a function f : d -> d is idempotent if
     
        	f f x = f x  for all x in d.
     
        i.e. repeated applications have the same effect as one.  this
        can be extended to functions of more than one argument,
        e.g. boolean  has x  x = x.  any value in the image of an
        idempotent function is a fixed point of the function.
     
        2. this term can be used to describe c header files, which
        contain common definitions and declarations to be included by
        several source files.  if a header file is ever included twice
        during the same compilation perhaps due to nested include
        files, compilation errors can result unless the header file
        has protected itself against multiple inclusion; a header file
        so protected is said to be idempotent.
     
        3. the term can also be used to describe an initialisation
        subroutine that is arranged to perform some critical action
        exactly once, even if the routine is called several times.
     
        jargon file
     
        1995-01-11
     
     
see also:
image fixed point c jargon file 

Idempotent >> I Words
Idempotent, definition of term: Idempotent
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