From Wikipedia
http://en.wikipedia.org/wiki/Algorithm
In
mathematics,
computing,
linguistics and
related disciplines, an algorithm is a
sequence of instructions, often used for
calculation,
data processing.
It is formally a type of
effective method
in which a list of welldefined instructions for
completing a task will, when given an initial
state, proceed through a welldefined series of
successive states, eventually terminating in an
endstate. The transition from one state to the
next is not necessarily
deterministic;
some algorithms, known as
probabilistic algorithms,
incorporate randomness.
A partial formalization of the concept began
with attempts to solve the
Entscheidungsproblem
(the "decision problem") posed by
David Hilbert
in 1928. Subsequent formalizations were framed
as attempts to define "effective
calculability" (Kleene 1943:274) or
"effective method" (Rosser 1939:225); those
formalizations included the GödelHerbrandKleene
recursive functions
of 1930, 1934 and 1935,
Alonzo Church's
lambda calculus
of 1936,
Emil Post's
"Formulation I" of 1936, and
Alan Turing's
Turing machines
of 19367 and 1939.
