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arXiv · 0811.3004

Extensions by Antiderivatives, Exponentials of Integrals and by Iterated Logarithms

V. Ravi Srinivasan
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Abstract

Let F be a characteristic zero differential field with an algebraically closed field of constants, E be a no-new-constant extension of F by antiderivatives of F and let y1, ..., yn be antiderivatives of E. The antiderivatives y1, ..., yn of E are called J-I-E antiderivatives if the derivatives of yi in E satisfies certain conditions. We will discuss a new proof for the Kolchin-Ostrowski theorem and generalize this theorem for a tower of extensions by J-I-E antiderivatives and use this generalized version of the theorem to classify the finitely differentially generated subfields of this tower. In the process, we will show that the J-I-E antiderivatives are algebraically independent over the ground differential field. An example of a J-I-E tower is extensions by iterated logarithms. We will discuss the normality of extensions by iterated logarithms and produce an algorithm to compute its finitely differentially generated subfields.

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V. Ravi Srinivasan. 2008-11-18. Extensions by Antiderivatives, Exponentials of Integrals and by Iterated Logarithms. https://arxiv.org/abs/0811.3004

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