2025/12/20
Seyed Hassan Alavi

Seyed Hassan Alavi

Academic rank: Professor
ORCID: https://orcid.org/0000-0002-6442-2507
Education: PhD.
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Faculty: Faculty of Science
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E-mail: alavi.s.hassan [at] gmail.com
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Research

Title
A generalisation of Johnson graphs with an application to triple factorisations
Type
JournalPaper
Keywords
Johnson graph,Triple factorisation, Symmetric group, Rank 2 geometry
Year
2015
Journal DISCRETE MATHEMATICS
DOI
Researchers Seyed Hassan Alavi

Abstract

In this paper, we introduce a new generalisation of Johnson graphs. The study of these graphs is linked to the study of intransitive triple factorisations Sym ( Ω ) = ABA of the (fi- nite)symmetricgroup,wherethesubgroupsAandBareintransitivesubgroupsofSym ( Ω ) . Indeed, we give combinatorial arguments to investigate the conditions under which such factorisations exist. We also use combinatorial arguments to study those conditions for which Sym ( Ω ) is a Geometric ABA-group, that is to say, Sym ( Ω ) = ABA, A ̸⊆ B, B ̸⊆ A and AB ∩ BA = A ∪ B