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On the finiteness of solutions for polynomial-factorial Diophantine equations

  • Wataru Takeda ORCID logo EMAIL logo
From the journal Forum Mathematicum

Abstract

We study the Diophantine equations obtained by equating a polynomial and the factorial function, and prove the finiteness of integer solutions under certain conditions. For example, we show that there exist only finitely many l such that l! is represented by NA(x), where NA is a norm form constructed from the field norm of a field extension K/𝐐. We also deal with the equation NA(x)=l!S, where l!S is the Bhargava factorial. In this paper, we also show that the Oesterlé–Masser conjecture implies that for any infinite subset S of 𝐙 and for any polynomial P(x)𝐙[x] of degree 2 or more the equation P(x)=l!S has only finitely many solutions (x,l). For some special infinite subsets S of 𝐙, we can show the finiteness of solutions for the equation P(x)=l!S unconditionally.


Communicated by Valentin Blomer


Award Identifier / Grant number: 19J10705

Funding statement: This work was supported by Grant-in-Aid for JSPS Research Fellow (Grant Number: 19J10705).

Acknowledgements

The author deeply expresses their sincere gratitude to Professor M. Ram Murty and Professor Andrzej Dąbrowski for fruitful discussions. The author also deeply thanks Professor Kohji Matsumoto and Professor Masatoshi Suzuki for their precious advice.

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Received: 2020-06-01
Revised: 2020-11-08
Published Online: 2020-12-12
Published in Print: 2021-03-01

© 2020 Walter de Gruyter GmbH, Berlin/Boston

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