# Relax, but Don't be Too Lazy

@article{Hoeven2002RelaxBD, title={Relax, but Don't be Too Lazy}, author={Joris van der Hoeven}, journal={J. Symb. Comput.}, year={2002}, volume={34}, pages={479-542} }

Assume that we wish to expand the product h = fg of two formal power series f and g. Classically, there are two types of algorithms to do this: zealous algorithms first expand f and g up to order n, multiply the results and truncate at order n. Lazy algorithms on the contrary compute the coefficients of f, g and h gradually and they perform no more computations than strictly necessary at each stage. In particular, at the moment we compute the coefficient hi of zi in h, only f0,..., fi and g0…

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