Abstract
Let R be the ring of S-integers of an algebraic function field (in one variable) over a perfect field, where S is finite and not empty. It is shown that for every positive integer N there exist elements of R that can not be written as a sum of at most N units. Moreover, all quadratic global function fields whose rings of integers are generated by their units are determined.
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Communicated by U. Zannier.
C. Frei is supported by the Austrian Science Foundation (FWF) project S9611-N23.
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Frei, C. Sums of units in function fields. Monatsh Math 164, 39–54 (2011). https://doi.org/10.1007/s00605-010-0219-7
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DOI: https://doi.org/10.1007/s00605-010-0219-7