释义 |
Tau FunctionA function related to the Divisor Function , also sometimes called Ramanujan's TauFunction. It is given by the Generating Function
 | (1) |
and the first few values are 1, , 252, , 4380, ... (Sloane's A000594). is also given by
 | (2) |
 | (3) |
 | (4) |
In Ore's Conjecture, the tau function appears as the number of Divisors of .Ramanujan conjectured and Mordell proved that if , then
 | (5) |
Ramanujan conjectured and Watson proved that is divisible by 691 for almost all . If
 | (6) |
then
 | (7) |
Values of for which the first equation holds are , 3, 5, 7, 23.
Ramanujan also studied
 | (8) |
which has properties analogous to the Riemann Zeta Function. It satisfies
 | (9) |
and Ramanujan's Tau-Dirichlet Series conjecture alleges that all nontrivial zeros of lie on the line . can be split up into
 | (10) |
where
The Summatory tau function is given by
 | (13) |
Here, the prime indicates that when is an Integer, the last term should be replaced by .
Ramanujan's tau theta function is a Real function for Real and isanalogous to the Riemann-Siegel Function . The number of zeros in the critical stripfrom to is given by
 | (14) |
where is the Riemann Theta Function and is the Tau-Dirichlet Series, defined by
 | (15) |
Ramanujan conjectured that the nontrivial zeros of the function are all real.
Ramanujan's function is defined by
 | (16) |
where is the Tau-Dirichlet Series.See also Ore's Conjecture, Tau Conjecture, Tau-Dirichlet Series References
Hardy, G. H. ``Ramanujan's Function .'' Ch. 10 in Ramanujan: Twelve Lectures on Subjects Suggested by His Life and Work, 3rd ed. New York: Chelsea, 1959.Sloane, N. J. A. SequenceA000594/M5153in ``An On-Line Version of the Encyclopedia of Integer Sequences.''http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S.The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995.
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