21 citations · 22 across the 9 of their papers we have counts for
12 papers
Recursive constructions for block-transitive, poset-imprimitive two-designs
Carmen Amarra, Alice Devillers, Cheryl E. Praeger
We give two general constructions for -designs, that can be used recursively, and interchangeably, to produce new infinite families of -designs admitting block-transitive gro…
Block-transitive designs with a poset of imprimitive partitions
Carmen Amarra, Alice Devillers, Cheryl E. Praeger
We study block designs which admit an automorphism group that is transitive on blocks and points, and leaves invariant every partition in a given finite poset of partitions of the…
Higher-dimensional grid-imprimitive block-transitive designs
Seyed Hassan Alavi, Carmen Amarra, Ashraf Daneshkhah +2
It was shown in 1989 by Delandtsheer and Doyen that, for a -design with points and block size , a block-transitive group of automorphisms can be point-imprimitive (that i…
Chain-imprimitive, flag-transitive 2-designs
Carmen Amarra, Alice Devillers, Cheryl E. Praeger
We consider -designs which admit a group of automorphisms that is flag-transitive and leaves invariant a chain of nontrivial point-partitions. We build on our recent work on …
The girth, odd girth, distance function, and diameter of generalized Johnson graphs
John S. Caughman, Ari J. Herman, Taiyo S. Terada
For any non-negative integers , the {\em generalized Johnson graph}, , is the undirected simple graph whose vertices are the -subsets of a -set, and wher…
Block-transitive 2-designs with a chain of imprimitive partitions
Carmen Amarra, Alice Devillers, Cheryl E. Praeger
More than years ago, Delandtsheer and Doyen showed that the automorphism group of a block-transitive -design, with blocks of size , could leave invariant a nontrivial po…
Multiple contractions of permutation arrays
Carmen Amarra, Dom Vito A. Briones, Manuel Joseph C. Loquias
Given a permutation on symbols and an integer , the th contraction of is the permutation on symbols…
Delandtsheer--Doyen parameters for block-transitive point-imprimitive 2-designs
Carmen Amarra, Alice Devillers, Cheryl E. Praeger
Delandtsheer and Doyen bounded, in terms of the block size, the number of points of a point-imprimitive, block-transitive 2-design. To do this they introduced two integer parameter…
Generalised shuffle groups
Carmen Amarra, Luke Morgan, Cheryl E. Praeger
The mathematics of shuffling a deck of cards with two "perfect shuffles" was brought into clarity by Diaconis, Graham and Kantor. Here we consider a generalisation of this pro…
On locally grid graphs
Carmen Amarra, Wei Jin, Cheryl E. Praeger
We investigate locally grid graphs, that is, graphs in which the neighbourhood of any vertex is the Cartesian product of two complete graphs on vertices. We consid…
Quotient-complete arc-transitive latin square graphs from groups
Carmen Amarra
We consider latin square graphs of the Cayley table of a given finite group . We characterize all pairs , where is a subgroup of autoparatopisms of t…
Affine primitive symmetric graphs of diameter two
Carmen Amarra, Michael Giudici, Cheryl E. Praeger
Let be a positive integer, be a prime power, and be a vector space of dimension over . Let , where is an irreducible subgrou…