Abstract
Using the decomposition of an automorphism of the ring of formal power series in several variables, in a semisimple and a unipotent automorphism, I prove in this paper that an automorphism allows a continuous iteration if and only if it is the exponential of a derivation. This result implies a number of results recently obtained by Reich, Schwaiger, and Bucher.
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Praagman, C. Iterations and logarithms of formal automorphisms. Aeq. Math. 30, 151–160 (1986). https://doi.org/10.1007/BF02189922
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DOI: https://doi.org/10.1007/BF02189922