Abstract
A square matrix V is called rigid if every matrix V' obtained by altering a small number of entries of $V$ has sufficiently high rank. While random matrices are rigid with high probability, no explicit constructions of rigid matrices are known to date. Obtaining such explicit matrices would have major implications in computational complexity theory. One approach to establishing rigidity of a matrix V is to come up with a property that is satisfied by any collection of vectors arising from a lowdimensional space, but is not satisfied by the rows of V even after alterations. In this paper we propose such a candidate property that has the potential of establishing rigidity of combinatorial design matrices over the field F_2.
Stated informally, we conjecture that under a suitable embedding of F_2^n into R^n, vectors arising from a low dimensional F_2linear space always have somewhat small Kolmogorov width, i.e., admit a nontrivial simultaneous approximation by a low dimensional Euclidean space. This implies rigidity of combinatorial designs, as their rows do not admit such an approximation even after alterations. Our main technical contribution is a collection of results establishing weaker forms and special cases of the conjecture above.
BibTeX  Entry
@InProceedings{samorodnitsky_et_al:LIPIcs:2015:5070,
author = {Alex Samorodnitsky and Ilya Shkredov and Sergey Yekhanin},
title = {{Kolmogorov Width of Discrete Linear Spaces: an Approach to Matrix Rigidity}},
booktitle = {30th Conference on Computational Complexity (CCC 2015)},
pages = {347364},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {9783939897811},
ISSN = {18688969},
year = {2015},
volume = {33},
editor = {David Zuckerman},
publisher = {Schloss DagstuhlLeibnizZentrum fuer Informatik},
address = {Dagstuhl, Germany},
URL = {http://drops.dagstuhl.de/opus/volltexte/2015/5070},
URN = {urn:nbn:de:0030drops50703},
doi = {10.4230/LIPIcs.CCC.2015.347},
annote = {Keywords: Matrix rigidity, linear codes, Kolmogorov width}
}
Keywords: 

Matrix rigidity, linear codes, Kolmogorov width 
Collection: 

30th Conference on Computational Complexity (CCC 2015) 
Issue Date: 

2015 
Date of publication: 

06.06.2015 