© 2002 by London Mathematical Society
© The London Mathematical Society
Unit Fractions and the Class Number of a Cyclotomic Field
Department of Mathematics, University of California Berkeley, CA 94720-3840, USA, ecroot{at}math.berkeley.edu
Department of Mathematics, University of Georgia Athens, GA 30602, USA, andrew{at}math.uga.edu
Received 28 November 2000. Revision received 7 January 2002.
Kummer's incorrect conjectured asymptotic estimate for the size of the first factor of the class number of a cyclotomic field, h1(p), is further examined. Whereas Kummer conjectured that h1(p)
G(p):= 2p(p/4
2)(p1)/4 it is shown, under certain plausible assumptions, that there exist constants a
, b
such that h1(p)
G(p) for
a
x/logb
x primes p
x whenever log
is rational. On the other hand, there are <<A x/logA x such primes when log
is irrational. Under a weak assumption it is shown that there are roughly the conjectured number of prime pairs p, mp±1 if and only if there are >>m x/log2 x primes p
x for which h1(p)
e±1/2mG(p).