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Counting and Detecting Small Subgraphs via Equations

Kowaluk, Miroslaw ; Lingas, Andrzej LU and Lundell, Eva-Marta LU (2013) In SIAM Journal on Discrete Mathematics 27(2). p.892-909
Abstract
We present a general technique for detecting and counting small subgraphs. It consists of forming special linear combinations of the numbers of occurrences of different induced subgraphs of fixed size in a graph. These combinations can be efficiently computed by rectangular matrix multiplication. Our two main results utilizing the technique are as follows. Let H be a fixed graph with k vertices and an independent set of size s. 1. Detecting if an n-vertex graph contains a (not necessarily induced) subgraph isomorphic to H can be done in time O(n(omega(inverte right perpendicular(k-s)/2inverted letf perpendicular,1,1 right perpendicular(k- s)/2inverted letf perpendicular))), where omega(p, q, r) is the exponent of fast arithmetic matrix... (More)
We present a general technique for detecting and counting small subgraphs. It consists of forming special linear combinations of the numbers of occurrences of different induced subgraphs of fixed size in a graph. These combinations can be efficiently computed by rectangular matrix multiplication. Our two main results utilizing the technique are as follows. Let H be a fixed graph with k vertices and an independent set of size s. 1. Detecting if an n-vertex graph contains a (not necessarily induced) subgraph isomorphic to H can be done in time O(n(omega(inverte right perpendicular(k-s)/2inverted letf perpendicular,1,1 right perpendicular(k- s)/2inverted letf perpendicular))), where omega(p, q, r) is the exponent of fast arithmetic matrix multiplication of an n(p) x n(q) matrix by an n(q) x n(r) matrix. 2. When s = 2, counting the number of (not necessarily induced) subgraphs isomorphic to H can be done in the same time, i.e., in time O(n(omega(inverted right perpendicular(k-2)/2inverted left perpendicular,1, inverted right perpendicular(k-2)/2inverted left perpendicular))). It follows in particular that we can count the number of subgraphs isomorphic to any H on four vertices that is not K-4 in time O(n(omega)), where omega = omega(1, 1, 1) is known to be smaller than 2.373. Similarly, we can count the number of subgraphs isomorphic to any H on five vertices that is not K-5 in time O(n(omega(2,1,1))), where omega(2, 1, 1) is known to be smaller than 3.257. Finally, we derive input-sensitive variants of our time upper bounds. They are partially expressed in terms of the number m of edges of the input graph and do not rely on fast matrix multiplication. (Less)
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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
subgraph and induced subgraph isomorphism, counting and detection of, subgraphs, linear equations, exact algorithms, rectangular matrix, multiplication
in
SIAM Journal on Discrete Mathematics
volume
27
issue
2
pages
892 - 909
publisher
Society for Industrial and Applied Mathematics
external identifiers
  • wos:000321042800018
  • scopus:84880414451
ISSN
0895-4801
DOI
10.1137/110859798
language
English
LU publication?
yes
id
77224fca-27ac-4e31-82b7-d43f262cd7ca (old id 3979396)
date added to LUP
2016-04-01 14:09:25
date last changed
2022-03-14 03:56:09
@article{77224fca-27ac-4e31-82b7-d43f262cd7ca,
  abstract     = {{We present a general technique for detecting and counting small subgraphs. It consists of forming special linear combinations of the numbers of occurrences of different induced subgraphs of fixed size in a graph. These combinations can be efficiently computed by rectangular matrix multiplication. Our two main results utilizing the technique are as follows. Let H be a fixed graph with k vertices and an independent set of size s. 1. Detecting if an n-vertex graph contains a (not necessarily induced) subgraph isomorphic to H can be done in time O(n(omega(inverte right perpendicular(k-s)/2inverted letf perpendicular,1,1 right perpendicular(k- s)/2inverted letf perpendicular))), where omega(p, q, r) is the exponent of fast arithmetic matrix multiplication of an n(p) x n(q) matrix by an n(q) x n(r) matrix. 2. When s = 2, counting the number of (not necessarily induced) subgraphs isomorphic to H can be done in the same time, i.e., in time O(n(omega(inverted right perpendicular(k-2)/2inverted left perpendicular,1, inverted right perpendicular(k-2)/2inverted left perpendicular))). It follows in particular that we can count the number of subgraphs isomorphic to any H on four vertices that is not K-4 in time O(n(omega)), where omega = omega(1, 1, 1) is known to be smaller than 2.373. Similarly, we can count the number of subgraphs isomorphic to any H on five vertices that is not K-5 in time O(n(omega(2,1,1))), where omega(2, 1, 1) is known to be smaller than 3.257. Finally, we derive input-sensitive variants of our time upper bounds. They are partially expressed in terms of the number m of edges of the input graph and do not rely on fast matrix multiplication.}},
  author       = {{Kowaluk, Miroslaw and Lingas, Andrzej and Lundell, Eva-Marta}},
  issn         = {{0895-4801}},
  keywords     = {{subgraph and induced subgraph isomorphism; counting and detection of; subgraphs; linear equations; exact algorithms; rectangular matrix; multiplication}},
  language     = {{eng}},
  number       = {{2}},
  pages        = {{892--909}},
  publisher    = {{Society for Industrial and Applied Mathematics}},
  series       = {{SIAM Journal on Discrete Mathematics}},
  title        = {{Counting and Detecting Small Subgraphs via Equations}},
  url          = {{http://dx.doi.org/10.1137/110859798}},
  doi          = {{10.1137/110859798}},
  volume       = {{27}},
  year         = {{2013}},
}