Bridge-addability, edge-expansion and connectivity

A class of graphs is called bridge-addable if, for each graph in the class and each pair u and v of vertices in different components, the graph obtained by adding an edge joining u and v must also be in the class. The concept was introduced in 2005 by McDiarmid, Steger and Welsh, who showed that, fo...

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Main Authors: McDiarmid, C, Weller, K
Format: Journal article
Published: Cambridge University Press 2017
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author McDiarmid, C
Weller, K
author_facet McDiarmid, C
Weller, K
author_sort McDiarmid, C
collection OXFORD
description A class of graphs is called bridge-addable if, for each graph in the class and each pair u and v of vertices in different components, the graph obtained by adding an edge joining u and v must also be in the class. The concept was introduced in 2005 by McDiarmid, Steger and Welsh, who showed that, for a random graph sampled uniformly from such a class, the probability that it is connected is at least 1/e. We generalize this and related results to bridge-addable classes with edge-weights which have an edge-expansion property. Here, a graph is sampled with probability proportional to the product of its edge-weights. We obtain for example lower bounds for the probability of connectedness of a graph sampled uniformly from a relatively bridge-addable class of graphs, where some but not necessarily all of the possible bridges are allowed to be introduced. Furthermore, we investigate whether these bounds are tight, and in particular give detailed results about random forests in complete balanced multipartite graphs.
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spelling oxford-uuid:c3072252-2c7e-4e87-a2dc-1d63ff97cec12022-03-27T06:13:29ZBridge-addability, edge-expansion and connectivityJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:c3072252-2c7e-4e87-a2dc-1d63ff97cec1Symplectic Elements at OxfordCambridge University Press2017McDiarmid, CWeller, KA class of graphs is called bridge-addable if, for each graph in the class and each pair u and v of vertices in different components, the graph obtained by adding an edge joining u and v must also be in the class. The concept was introduced in 2005 by McDiarmid, Steger and Welsh, who showed that, for a random graph sampled uniformly from such a class, the probability that it is connected is at least 1/e. We generalize this and related results to bridge-addable classes with edge-weights which have an edge-expansion property. Here, a graph is sampled with probability proportional to the product of its edge-weights. We obtain for example lower bounds for the probability of connectedness of a graph sampled uniformly from a relatively bridge-addable class of graphs, where some but not necessarily all of the possible bridges are allowed to be introduced. Furthermore, we investigate whether these bounds are tight, and in particular give detailed results about random forests in complete balanced multipartite graphs.
spellingShingle McDiarmid, C
Weller, K
Bridge-addability, edge-expansion and connectivity
title Bridge-addability, edge-expansion and connectivity
title_full Bridge-addability, edge-expansion and connectivity
title_fullStr Bridge-addability, edge-expansion and connectivity
title_full_unstemmed Bridge-addability, edge-expansion and connectivity
title_short Bridge-addability, edge-expansion and connectivity
title_sort bridge addability edge expansion and connectivity
work_keys_str_mv AT mcdiarmidc bridgeaddabilityedgeexpansionandconnectivity
AT wellerk bridgeaddabilityedgeexpansionandconnectivity