  A. Speiser proved that the Riemann hypothesis is equivalent to the absence of
non-real zeros of the derivative of the Riemann zeta-function left of the
critical line. His result has been extended by N. Levinson and H.L. Montgomery
to the statement that the Riemann zeta-function and its derivative have
approximately the same number of non-real zeros left of the critical line. We
obtain the Levinson-Montgomery type result for the Lerch zeta-function with
equal parameters. For the Lerch zeta-function, the analogue of the Riemann
hypothesis is usually not true and its zeros usually are distributed
asymmetrically with respect to the critical line. However, for equal
parameters, the symmetry of the zeros is almost restored.
