A matrix called Varchenko matrix associated with a hyperplane arrangement was defined by Varchenko in 1991. Matrices that we shall call q-matrices are induced from Varchenko matrices. Many researchers are interested in the invariant factors of these q-matrices. In this paper, we associate this problem with a graph theoretic model. We will discuss some general properties and give some methods fo...

in this article, we verify existence and uniqueness of positive and nondecreasing solution for nonlinear boundary value problem of fractional differential equation in the form d_{0^{+}}^{alpha}x(t)+f(t,x(t))=0, 0x(0)= x'(0)=0, x'(1)=beta x(xi), where $d_{0^{+}}^{alpha}$ denotes the standard riemann-liouville fractional derivative, 0an illustrative example is also presented.

This paper addresses a necessary and sufficient robust stability condition of fractional-order interval linear time invariant systems. The state matrix A is considered as a parametric interval uncertain matrix and fractional commensurate order is considered belonging to 1 ≤ α < 2. Using the existence condition of Hermitian matrix P = P ∗ for a complex Lyapunov inequality, we show that a fractio...

We present the method of group foliation for constructing non-invariant solutions of partial differential equations on an important example of the Boyer-Finley equation from the theory of gravitational instantons. We show that the commutativity constraint for a pair of invariant differential operators leads to a set of non-invariant solutions of this equation. In the second part of the paper we...

In this thesis we use a semidefinite programming approach to find explicit upper bounds on the size of ternary constant weight codes with prescribed minimum distance d. By constructing a graph Γ = (X,E), on the set, X, of all possible ternary words of weight w letting {x, y} ∈ E ⇔ 0 < dH(x, y) < d, we can view this problem as a special case of the stable set problem. Using symmetry, the constra...