A class of hypertranscendental functions
A class of hypertranscendental functions
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一类超超越函数
DOI:
10.1007/bf01836423
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发表时间:
1977
期刊:
影响因子:
--
通讯作者:
A. J. Poorten
中科院分区:
文献类型:
--
作者:
J. Loxton;A. J. Poorten
A hypertranscendental function is one which does not satisfy any algebraic differential equation. Some well-known examples of such functions are the zeta function of Riemann and the zeta functions of algebraic number fields.(See [4]). In this note, we study the hypertranscendence of functions satisfying functional equations of the type described in Section 8 below. We obtain also, in Sections 3 to 7, conditions under which a set of functions satisfying functional equations of this type is algebraically independent over the field of rational functions; in fact this is the main step in the proof of the hypertranscendence result which we prove in Section 8. Finally, Section 9 contains some examples illustrative of the foregoing analysis.In a series of papers culminating in [3], Mahler has obtained some very general results on the transcendence and algebraic independence of the values of functions satisfying functional equations of the type considered here. One part of the argument is to investigate the transcendence and algebraic independence of the functions themselves.(See [3], pages 549-556). Our results are in the same spirit as those given by Mahler, but we consider a more general class of functional equations. We also hope to have repaired some omissions in [3], as a consequence of which the main result on page 554 of [3] is incorrect as stated. We would like to thank Professor Mahler for drawing our attention to his paper [3] and to acknowledge our debt to the ideas he develops there.