Browsing Mathematics & Statistics Faculty by Issue Date
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An ErdosKoRado theorem for the derangement graph of PGL(2,q) acting on the projective plane
(SIAM Journal on Discrete Mathematics, 2014)Let G = PGL(2, q) be the projective general linear group acting on the projec tive line P_q. A subset S of G is intersecting if for any pair of permutations \pi and \sigma in S, there is a projective point p in P_q such ... 
An ErdősKoRado theorem for the derangement graph of \(PGL_3(q)\) acting on the projective plane
(SIAM J. Discrete Math. 28, 2014)In this paper we prove an ErdősKoRadotype theorem for intersecting sets of permutations. We show that an intersecting set of maximal size in the projective general linear group \(PGL_3(q)\), in its natural ... 
Performance enhancement of doubling algorithms for a class of complex nonsymmetric algebraic Riccati equations
(Oxford University Press, 2014)A new class of complex nonsymmetric algebraic Riccati equations has been studied by Liu and Xue (SIAM J. Matrix Anal. Appl., 33 (2012), 569596), which is related to the Mmatrix algebraic Riccati equations. Doubling ... 
The principal rank characteristic sequence over various fields
(Elsevier, 2014)Given an nbyn matrix, its principal rank characteristic sequence is a sequence of length n + 1 of 0s and 1s where, for k = 0; 1,..., n, a 1 in the kth position indicates the existence of a principal submatrix of rank ... 
Intersecting generalized permutations
(20140121) 
C.V.
(20140121) 
A convergence result for matrix Riccati differential equations associated with Mmatrices
(20140422)The initial value problem for a matrix Riccati differential equation associated with an $M$matrix is known to have a global solution $X(t)$ on $[0, \infty)$ when $X(0)$ takes values from a suitable set of nonnegative ... 
The maximum nullity of a complete edge subdivision graph is equal to it zero forcing number
(International Linear Algebra Society, 201406)Barrett et al. asked in [W. Barrett et al. Minimum rank of edge subdivisions of graphs. Electronic Journal of Linear Algebra, 18:530–563, 2009.], whether the maximum nullity is equal to the zero forcing number for all ... 
On the complexity of the positive semidefinite zero forcing number
(Elsevier, 2015)The positive semidefinite zero forcing number of a graph is a graph parameter that arises from a nontraditional type of graph colouring and is related to a more conventional version of zero forcing. We establish a relation ... 
The enhanced principal rank characteristic sequence
(Elsevier, 2015)The enhanced principal rank characteristic sequence (eprsequence) of a symmetric n ×n matrix is a sequence from A,S, or N according as all, some, or none of its principal minors of order k are nonzero. Such sequences give ... 
The enhanced principal rank characteristic sequence for skewsymmetric matrices
(Elsevier, 20150815)The enhanced principal rank characteristic sequence (eprsequence) was originally defined for an n ×n real symmetric matrix or an n ×n Hermitian matrix. Such a sequence is defined to be l1l2···ln where lk is A,S, or N ... 
An ErdősKoRado theorem for finite \(2\)transitive groups
(European Journal of Combinatorics, 2016)We prove an analogue of the classical ErdősKoRado theorem for intersecting sets of permutations in finite \(2\)transitive groups. Given a finite group \(G\) acting faithfully and \(2\)transitively on the set ... 
MIKL´ OSMANICKAMSINGHI CONJECTURES ON PARTIAL GEOMETRIES
(201606)In this paper we give a proof of the Mikl´osManickamSinghi (MMS) conjecture for some partial geometries. Specifically, we give a condition on partial geometries which implies that the MMS conjecture holds. Further, ...