Deriving an inequality from a paper

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Discussion Overview

The discussion revolves around the derivation of an inequality presented in a paper by Yann Bugeaud, specifically inequality (16) found on page 13. Participants are seeking clarification on the derivation process and addressing issues related to the mathematical expressions involved.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant requests help in deriving inequality (16) from the paper, noting that previous attempts have encountered problems.
  • Another participant points out the absence of equations in the initial post, suggesting that the lack of clarity may hinder the discussion.
  • A participant proposes examining the expression involving the ratios of the parameters and suggests that additional relations may arise from the fact that the pairs are Lucas pairs.
  • There is a suggestion to express the left-hand side of the inequality as a power series in one of the parameters and to estimate the coefficients to aid in the derivation.
  • One participant discusses a specific condition involving the parameter η, suggesting that under certain assumptions, the quotient approaches a specific value.
  • Another participant emphasizes that the condition depends solely on the Lucas pairs and expresses uncertainty about the relationship between the equations without having read the paper in detail.
  • There is a request for others to review specific pages of the paper for necessary information related to the query.
  • Participants express ongoing difficulty in achieving the desired result despite multiple attempts and seek further assistance.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the derivation of the inequality, with multiple competing views and unresolved questions remaining in the discussion.

Contextual Notes

Participants note gaps in the original post regarding mathematical expressions, which may affect the clarity of the discussion. There are also unresolved assumptions related to the parameter η and its implications for the derivation.

Andrew_99
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Hi, I am studying a paper by Yann Bugeaud:

http://irma.math.unistra.fr/~bugeaud/travaux/ConfMumbaidef.pdf
on page 13 there is an inequality (16) as given below-

attachment.php


which is obtained from -

attachment.php


, on page 12.

How the inequality (16) is derived? I couldn't figure it out. However one of my forum member

tried but it has two problems (problems are marked as "how?"), it is given below-

attachment.php


It is not clear how those two questions would be resolved.

Can anyone show the derivation of inequality (16)?

Thanks in Advance.
 
Last edited by a moderator:
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Are you missing the latex or images for the equations of interest in your post?

I see gaps but no equations.

POSTSCRIPT: I also had to edit your post to make the link more explicit. We sometimes get posts like this that are actually spam with hidden links.
 
Multiplying it leads to the question whether
$$
\left|\dfrac{\beta^m}{\gamma^n} \cdot \dfrac{\gamma-\delta}{\alpha-\beta}- \dfrac{\delta^n}{\gamma^n} \right| \ll \dfrac{1}{\alpha^{\eta(m-1)}}
$$
given ##\alpha \geq \gamma \geq |\delta|^{1+\eta}\, , \,\alpha \geq |\beta|^{1+\eta}##.

Are there additional relations by the fact that ##(\alpha,\beta)## and ##(\gamma,\delta)## are Lucas pairs?
An idea could be to write the left hand side as a power series in ##\alpha## and estimate the coefficients.
 
jedishrfu said:
Are you missing the latex or images for the equations of interest in your post?

I see gaps but no equations.

POSTSCRIPT: I also had to edit your post to make the link more explicit. We sometimes get posts like this that are actually spam with hidden links.
I used Image from paper.
 
fresh_42 said:
Are there additional relations by the fact that ##(\alpha,\beta)## and ##(\gamma,\delta)## are Lucas pairs?
An idea could be to write the left hand side as a power series in ##\alpha## and estimate the coefficients.
I tried, two other persons tried, see the last image, but failed to get the result, Plz help.
 
Andrew_99 said:
I tried, two other persons tried, see the last image, but failed to get the result, Plz help.
fresh_42 said:
Are there additional relations by the fact that ##(\alpha,\beta)## and ##(\gamma,\delta)## are Lucas pairs?

As far as I can see, there is no restriction on ##\eta## except ##0<\eta <\frac{1}{2}.## Let us assume that ##\eta## is close to zero. Then the assertion is that ##0 \ll \dfrac{\alpha (\gamma - \delta)}{\gamma (\alpha -\beta)} \cdot \dfrac{\alpha^{dr}}{\gamma^{ds}}\ll 2##, i.e. the quotient is close to ##1## in this case. This can be written as ##\alpha^m \gamma +\gamma^n \beta \approx \gamma^n\alpha + \alpha^m \delta##.

As this condition only depends on the given Lucas pairs ##u_m(\alpha,\beta) = v_n(\gamma,\delta)##, I assume that both equations are related; which I don't know since I haven't read the paper. If so, then I would start here and look whether we can go backwards to
$$
\left| \dfrac{\alpha (\gamma - \delta)}{\gamma (\alpha -\beta)} \cdot \dfrac{\alpha^{dr}}{\gamma^{ds}} -1 \right| \ll \alpha^{-\eta rd}
$$
 
fresh_42 said:
As this condition only depends on the given Lucas pairs ##u_m(\alpha,\beta) = v_n(\gamma,\delta)##, I assume that both equations are related; which I don't know since I haven't read the paper.
Read page 12 and 13 (at most, page 10, 11) of below pdf file, for all information required for my query, no need to read the whole paper.
http://irma.math.unistra.fr/~bugeaud/travaux/ConfMumbaidef.pdf

The problem is algebraic derivation which I could not figure out.

You wrote-
fresh_42 said:
the assertion is that ## \dfrac{\alpha (\gamma - \delta)}{\gamma (\alpha -\beta)} \cdot \dfrac{\alpha^{dr}}{\gamma^{ds}}\ll 2##,
do you think
##\alpha^{-\eta rd} \approx 2## ? also please see our attempt in the last image of fist post.
anyway, please inform me if find anything, thanks.
 

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