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<h1 align=center> What is an $L$-function?
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The Riemann Hypothesis is an assertion about the zeros of
the Riemann $\zeta$-function.  Generalizations of the 
$\zeta$-function have been discovered, for which the analogue
of the Riemann Hypothesis is also conjectured.

These generalizations of the $\zeta$-function are known
as ``zeta-functions'' or ``$L$-functions.''  
In this section we describe attempts to determine the
collection of functions that deserve to be called L-functions.
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Back to the 
<a href="http://www.aimath.org/WWN/rh/"> main index</a> 
for The Riemann Hypothesis.
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