The Lang–Waldschmidt conjecture on linear forms in logarithms

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Let ϵ>0\epsilon>0, let a1,…,ana_1,\ldots,a_n be positive integers, and let b1,…,bnb_1,\ldots,b_n be non-zero integers such that a1b1⋯anbn≠1a_1^{b_1}\cdots a_n^{b_n}\ne 1. Lang–Waldschmidt conjecture. There is a number C(ϵ)C(\epsilon) depending only on ϵ\epsilon such that

∣a1b1⋯anbn−1∣≥C(ϵ)max⁡j∣bj∣∣b1⋯bna1⋯an∣1+ϵ.\left|a_1^{b_1}\cdots a_n^{b_n}-1\right|\ge \frac{C(\epsilon)\max_j|b_j|}{\left|b_1\cdots b_n a_1\cdots a_n\right|^{1+\epsilon}}.

The conjecture predicts a strong archimedean lower bound for non-vanishing multiplicative linear forms in logarithms. It is presented as an open conjecture motivating the paper's discussion of effective Diophantine approximation.

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Other statements of this same problem, merged from separate entries. Each is equivalent to the statement above — proving any one settles them all.

  1. Lang--Waldschmidt conjecture on linear forms in logarithms

    Let a1,…,an,b1,…,bna_1,\ldots,a_n,b_1,\ldots,b_n be non-zero integers and define

    Λ=∑ibilog⁡ai≠0.\Lambda=\sum_i b_i\log a_i\ne0.

    Set

    A=max⁡i∣ai∣,B=max⁡i∣bi∣.A=\max_i|a_i|,\qquad B=\max_i|b_i|.

    Lang--Waldschmidt conjecture. There is an effectively computable constant Cn>0C_n>0, depending only on nn, such that

    log⁡∣Λ∣⩾−Cn(log⁡A+log⁡B).\log|\Lambda|\geqslant-C_n(\log A+\log B).

    This is the Lang--Waldschmidt conjecture on Baker's logarithmic sum estimates, invoked in the source as a conditional tool for obtaining stronger estimates related to dyadic approximation. Its resolution status is not established by the supplied text.

    source: Demi Allen, Sam Chow and Han Yu, “Dyadic Approximation in the Middle-Third Cantor Set”, arXiv:2005.09300 (2020).

References

Primary source

Hector Pasten, “On the arithmetic case of Vojta's conjecture with truncated counting functions”, arXiv:2205.07841 (2022).

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