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What and Who
Title:Waring rank of monomial
Speaker:Nikhil Balaji
coming from:University of Ulm
Speakers Bio:
Event Type:AG1 Mittagsseminar (own work)
Visibility:D1, D2, D3, D4, D5, RG1, SWS, MMCI
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Level:AG Audience
Language:English
Date, Time and Location
Date:Thursday, 5 July 2018
Time:16:00
Duration:30 Minutes
Location:Saarbr├╝cken
Building:E1 4
Room:024
Abstract
The Waring rank of a degree-d multivariate polynomial F(x_1,... x_n) is the least number $r$ such that,


F(x_1,... x_n) = c_1\ell_1 + c_2\ell_2 + ... + c_r\ell_r

where \ell_i = \alpha_{i1}x_1 + \alpha_{i2}x_2 + ... \alpha_{in}x_n.

It follows from a simple application (due to Kayal) of the classical partial derivative method of Nisan and Wigderson that
the multilinear monomial $\prod_{i=1}^n x_i$ has Waring rank at least $2^n/\sqrt{n}$ and a result of Fischer gives an upper bound of $2^{n-1}$
A result due to Ranestad and Schreyer (2011) proves that the Waring rank of the multilinear monomial is exactly $2^{n-1}$. A follow up work of
Carlini, Catalisano and Geramita (2012) shows that the Waring rank of a general monomial $\prod_{i=1}^n x_i^{d_i}$ is exactly $\prod_{i=2}^n (d_i + 1)$.
Both these proofs crucially make use of the notion of Apolarity, a notion that dates back to Sylvester. We provide an alternate proof of both these results
and discuss a few natural related questions that remain unresolved.

Part of ongoing work with Nutan Limaye, Sai Sandeep, Srikanth Srinivasan and Thomas Thierauf.

Contact
Name(s):Nitin Saurabh
Video Broadcast
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Created:
Nitin Saurabh, 06/25/2018 05:11 PM
Last modified:
Uwe Brahm/MPII/DE, 07/05/2018 07:01 AM
  • Nitin Saurabh, 06/25/2018 05:11 PM -- Created document.