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A note on extensions of multilinear maps defined on multilinear varieties

Published online by Cambridge University Press:  30 April 2021

W. T. Gowers
Affiliation:
Collège de France and University of Cambridge, 11, Place Marcelin-Berthelot, Paris75231, France (wtg10@dpmms.cam.ac.uk)
L. Milićević
Affiliation:
Mathematical Institute of the Serbian Academy of Sciences and Arts, Kneza Mihaila 36, Belgrade11000, Serbia (luka.milicevic@turing.mi.sanu.ac.rs)

Abstract

Let $G_1, \ldots , G_k$ be finite-dimensional vector spaces over a prime field $\mathbb {F}_p$. A multilinear variety of codimension at most $d$ is a subset of $G_1 \times \cdots \times G_k$ defined as the zero set of $d$ forms, each of which is multilinear on some subset of the coordinates. A map $\phi$ defined on a multilinear variety $B$ is multilinear if for each coordinate $c$ and all choices of $x_i \in G_i$, $i\not =c$, the restriction map $y \mapsto \phi (x_1, \ldots , x_{c-1}, y, x_{c+1}, \ldots , x_k)$ is linear where defined. In this note, we show that a multilinear map defined on a multilinear variety of codimension at most $d$ coincides on a multilinear variety of codimension $O_{k}(d^{O_{k}(1)})$ with a multilinear map defined on the whole of $G_1\times \cdots \times G_k$. Additionally, in the case of general finite fields, we deduce similar (but slightly weaker) results.

Type
Research Article
Copyright
Copyright © The Author(s), 2021. Published by Cambridge University Press on Behalf of The Edinburgh Mathematical Society

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References

Bhowmick, A. and Lovett, S., Bias vs structure of polynomials in large fields, and applications in effective algebraic geometry and coding theory, arXiv preprint (2015), arXiv:1506.02047Google Scholar
Bienvenu, P.-Y. and , T. H., A bilinear Bogolyubov theorem, Eur. J. Comb. 77 (2019), 102113.10.1016/j.ejc.2018.11.003CrossRefGoogle Scholar
Bienvenu, P.-Y., González-Sánchez, D. and Martínez, Á., A note on the bilinear Bogolyubov theorem: transverse and bilinear sets, Proc. Am. Math. Soc. 148 (2020), 2331.10.1090/proc/14658CrossRefGoogle Scholar
Gowers, W. T. and Milićević, L., A quantitative inverse theorem for the $U^{4}$ norm over finite fields, arXiv preprint (2017), arXiv:1712.00241Google Scholar
Gowers, W. T. and Milićević, L., A bilinear version of Bogolyubov's theorem, Proc. Am. Math. Soc. 148 (2020), 46954704.10.1090/proc/15129CrossRefGoogle Scholar
Gowers, W. T. and Wolf, J., Linear forms and higher-degree uniformity for functions on $\mathbb {F}^{n}_p$, Geom. Funct. Anal. 21(1) (2011), 3669.10.1007/s00039-010-0106-3CrossRefGoogle Scholar
Hosseini, K. and Lovett, S., A bilinear Bogolyubov-Ruzsa lemma with polylogarithmic bounds, Discrete Anal. 10 (2019), 114.Google Scholar
Janzer, O., Polynomial bound for the partition rank vs the analytic rank of tensors, Discrete Anal. 7 (2020), 118.Google Scholar
Kazhdan, D. and Ziegler, T., Extending weakly polynomial functions from high rank varieties, arXiv preprint (2018), arXiv:1808.09439Google Scholar
Kazhdan, D. and Ziegler, T., Properties of high rank subvarieties of affine spaces, arXiv preprint (2019), arXiv:1902.00767Google Scholar
Lovett, S., The analytic rank of tensors and its applications, Discrete Anal. 7 (2019), 110.Google Scholar
Milićević, L., Polynomial bound for partition rank in terms of analytic rank, Geom. Funct. Anal. 29(5) (2019), 15031530.10.1007/s00039-019-00505-4CrossRefGoogle Scholar
Naslund, E., The partition rank of a tensor and $k$-right corners in $\mathbb {F}_q^{n}$, J. Comb. Theory, Ser. A 174 (2020), Article 105190.10.1016/j.jcta.2019.105190CrossRefGoogle Scholar