English

Some transcendence results from a harmless irrationality theorem

Number Theory 2017-07-06 v3

Abstract

The arithmetic nature of values of some functions of a single variable, particularly, sinz\sin{z}, cosz\cos{z}, sinhz\sinh{z}, coshz\cosh{z}, eze^z, and lnz\ln{z}, is a relevant topic in number theory. For instance, all those functions return transcendental values for all non-zero algebraic values of zz (z1z \ne 1 in the case of lnz\ln{z}). On the other hand, not even an irrationality proof is known for some numbers like ee\,e^e, πe\,\pi^e, ππ\,\pi^\pi, lnπ\,\ln{\pi}, π+e\,\pi + e\, and πe\,\pi \, e, though it is well-known that at least one of the last two numbers is irrational. In this note, I first derive a more general form of this last result, showing that at least one of the sum and product of any two transcendental numbers is transcendental. I then use this to show that, given any complex number t0,1/e\,t \ne 0, 1/e, at least two of the numbers lnt\,\ln{t}, t+e\,t + e\, and te\,t \, e\, are transcendental. I also show that coshz\,\cosh{z}, sinhz\sinh{z}\, and tanhz\,\tanh{z}\, return transcendental values for all z=rlnt\,z = r \, \ln{t}, rQ\,r \in \mathbb{Q}, r0r \ne 0. Finally, I use a recent algebraic independence result by Nesterenko to show that, for all integer n>0\,n > 0, lnπ\,\ln{\pi}\, and nπ\,\sqrt{n} \, \pi\, are linearly independent over Q\mathbb{Q}.

Keywords

Cite

@article{arxiv.1310.7289,
  title  = {Some transcendence results from a harmless irrationality theorem},
  author = {F. M. S. Lima},
  journal= {arXiv preprint arXiv:1310.7289},
  year   = {2017}
}

Comments

12 pages, no figures. Inclusion of a new theorem (Theor.3). Submitted to Expos. Math. (Feb/07/2014)

R2 v1 2026-06-22T01:55:04.994Z