We study the Berezin-Toeplitz quantization on Kaehler manifolds. We explain
first how to compute various associated asymptotic expansions, then we compute
explicitly the first terms of the expansion of the kernel of the
Berezin-Toeplitz operators, and of the composition of two Berezin-Toeplitz
operators. As application we estimate the norm of Donaldson's Q-operator.Comment: 45 pages, footnote at page 3 and Remark 0.5 added; v.3 is a final
update to agree with the published pape