License: Creative Commons Attribution 4.0 International license (CC BY 4.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.ICALP.2021.29
URN: urn:nbn:de:0030-drops-140988
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2021/14098/
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Björklund, Andreas ; Kaski, Petteri

Counting Short Vector Pairs by Inner Product and Relations to the Permanent

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LIPIcs-ICALP-2021-29.pdf (0.8 MB)

Abstract

Given as input two n-element sets A, B ⊆ {0,1}^d with d = clog n ≤ (log n)²/(log log n)⁴ and a target t ∈ {0,1,…,d}, we show how to count the number of pairs (x,y) ∈ A× B with integer inner product ⟨ x,y ⟩ = t deterministically, in n²/2^{Ω(√{log nlog log n/(clog² c)})} time. This demonstrates that one can solve this problem in deterministic subquadratic time almost up to log² n dimensions, nearly matching the dimension bound of a subquadratic randomized detection algorithm of Alman and Williams [FOCS 2015]. We also show how to modify their randomized algorithm to count the pairs w.h.p., to obtain a fast randomized algorithm.
Our deterministic algorithm builds on a novel technique of reconstructing a function from sum-aggregates by prime residues, or modular tomography, which can be seen as an additive analog of the Chinese Remainder Theorem.
As our second contribution, we relate the fine-grained complexity of the task of counting of vector pairs by inner product to the task of computing a zero-one matrix permanent over the integers.

BibTeX - Entry

@InProceedings{bjorklund_et_al:LIPIcs.ICALP.2021.29,
  author =	{Bj\"{o}rklund, Andreas and Kaski, Petteri},
  title =	{{Counting Short Vector Pairs by Inner Product and Relations to the Permanent}},
  booktitle =	{48th International Colloquium on Automata, Languages, and Programming (ICALP 2021)},
  pages =	{29:1--29:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-195-5},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{198},
  editor =	{Bansal, Nikhil and Merelli, Emanuela and Worrell, James},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/opus/volltexte/2021/14098},
  URN =		{urn:nbn:de:0030-drops-140988},
  doi =		{10.4230/LIPIcs.ICALP.2021.29},
  annote =	{Keywords: additive reconstruction, Chinese Remainder Theorem, counting, inner product, modular tomography, orthogonal vectors, permanent}
}

Keywords: additive reconstruction, Chinese Remainder Theorem, counting, inner product, modular tomography, orthogonal vectors, permanent
Collection: 48th International Colloquium on Automata, Languages, and Programming (ICALP 2021)
Issue Date: 2021
Date of publication: 02.07.2021

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