Abstract: | A trace formula expressing the mean values of the form (k=2,3,...) via certain arithmetic means on the group Г0(N1) is proved. Here the sum is taken over a normalized orthogonal basis in the space of holomorphic cusp forms of weight 2k
with respect to Г0(N1). By H
f
(x)
(s) we denote the Hecke series of the form f, twisted with the primitive character χ (mod N2), and λf(d), (d, N1N2)=1, are the eigenvalues of the Hecke operators. The trace formula is used for obtaining the estimate for the newform f for all ε>0, l=0,1,2,.... This improves the known result (Duke-Friedlander-Iwaniec, 1993) with upper bound
(1+|t|)2N
2
1/2−1/22+ε
on the right-hand side. As a corollary, we obtain the estimate for the Fourier coefficients of holomorphic cusp forms of weight k+1/2, which improves Iwaniec' result (1987) with exponent
1/4–1/28+ε. Bibliography: 25 titles.
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 226, 1996, pp. 14–36. |