arXiv subjects
Publications and source records attributed to Dušan Repovš.
We study the perturbation by a critical term and a $(p-1)$-superlinear subcritical nonlinearity of a quasilinear elliptic equation containing a singular potential. By means of variational arguments and a version of the concentration-compactness principle in the singular case, we prove the existence of solutions for positive values of the parameter under the principal eigenvalue of the associated singular eigenvalue problem.
We study polynomial identities of finite dimensional simple color Lie superalgebras over an algebraically closed field of characteristic zero graded by the product of two cyclic groups of order $2$. We prove that the codimensions of identities grow exponentially and the rate of exponent equals the dimension of the algebra. A similar result is also obtained for graded identities and graded codimensions.
We are concerned with the qualitative analysis of positive singular solutions with blow-up boundary for a class of logistic-type equations with slow diffusion and variable potential. We establish the exact blow-up rate of solutions near the boundary in terms of Karamata regular variation theory. This enables us to deduce the uniqueness of the singular solution.
We establish existence results of Hartmann-Stampacchia type for a class of variational-hemivariationalinequalities on closed and convex sets (either bounded or unbounded) in a Hilbert space.
We apply a recently obtained three critical points theorem of B. Ricceri to prove the existence of at least three solutions of certain two-parameters Dirichlet problems defined on the Sierpinski gasket. We also show the existence of at least three nonzero solutions of certain perturbed two-parameters Dirichlet problems on the Sierpinski gasket, using both the mountain pass theorem of Ambrosetti-Rabinowitz and that of Pucci-Serrin.
In this paper we prove an existence result for a general class of hemivariational inequalities systems using the Ky Fan version of KKM theorem (1984) or the Tarafdar fixed point theorem (1987). As application we give an infinite dimensional version for existence result of Nash generalized derivative points introduced recently by Kristály (2010) and also we give an application to a general hemivariational inequalities system.
We study codimension growth of infinite dimensional Lie superalgebras over an algebraically closed field of characteristic zero. We prove that if a Lie superalgebra $L$ is a Grassmann envelope of a finite dimensional simple Lie algebra then the PI-exponent of $L$ exists and it is a positive integer.
We study $\mathbb{Z}_2$-graded identities of Lie superalgebras of the type $b(t), t\ge 2$, over a field of characteristic zero. Our main result is that the $n$-th codimension is strictly less than $(\dim b(t))^n$ asymptotically. As a consequence we obtain an upper bound for ordinary (non-graded) PI-exponent for each simple Lie superalgebra $b(t), t\ge 3$.
We study asymptotic behaviour of graded codimensions of Lie superalgebra $b(2)$. We prove that graded PI-exponent exists and is equal to $3+2\sqrt 3$.
We study gradings by noncommutative groups on finite dimensional Lie algebras over an algebraically closed field of characteristic zero. It is shown that if $L$ is gradeg by a non-abelian finite group $G$ then the solvable radical $R$ of $L$ is $G$-graded and there exists a Levi subalgebra $B=H_1\oplus\cdots\oplus H_m$ homogeneous in $G$-grading with graded simple summands $H_1, \ldots, H_m$. All supports $Supp~H_i, i=1\ldots, m$, are commutative subsets of $G$.
In this paper two metric properties on geodesic length spaces are introduced by means of the metric projection, studying their validity on Alexandrov and Busemann NPC spaces. In particular, we prove that both properties characterize the non-positivity of the sectional curvature on Riemannian manifolds. Further results are also established on reversible/non-reversible Finsler-Minkowski spaces.
We prove that if $\mathcal{A}$ is a complex, unital semisimple Banach algebra and $\mathcal{B}$ is a complex, unital Banach algebra having a separating family of finite-dimensional irreducible representations, then any unital linear operator from $\mathcal{A}$ onto $\mathcal{B}$ which preserves the spectral radius is a Jordan morphism.
In this paper we consider the model semilinear Neumann system $$\left\{ \begin{array}{lll} -Δu+a(x)u=λc(x) F_u(u,v)& {\rm in} & Ω,\\ -Δv+b(x)v=λc(x) F_v(u,v)& {\rm in} & Ω,\\ \frac{\partial u}{\partial ν}=\frac{\partial v}{\partial ν}=0 & {\rm on} & \partialΩ, \end{array}\right.$$ where $Ω\subset \mathbb R^N$ is a smooth open bounded domain, $ν$ denotes the outward unit normal to $\partial Ω$, $λ\geq 0$ is a parameter, $a,b,c\in L_+^\infty(Ω)\setminus\{0\},$ and $F\in C^1(\mathbb{R}^2,\mathbb{R})\setminus\{0\}$ is a nonnegative function which is subquadratic at infinity. Two nearby numbers are determined in explicit forms, $\underline λ$ and $\overline λ$ with $ 0<\underlineλ\leq \overline λ$, such that for every $0\leq λ<\underline λ$, system $(N_λ)$ has only the trivial pair of solution, while for every $λ>\overline λ$, system $(N_λ)$ has at least two distinct nonzero pairs of solutions.
In this paper we study the coupled Schrödinger-Maxwell system $$\left\{ \begin{array}{lll} -\triangle u+u +ϕu=λα(x) f(u)& {\rm in} & \mathbb R^3,\\ -\triangle ϕ=u^2 & {\rm in} & \mathbb R^3, \end{array}\right. $$ where $α\in L^\infty(\mathbb R^3)\cap L^{6/(5-q)}(\mathbb R^3)$ for some $q\in (0,1)$, and the continuous function $f:\mathbb{R}\to\mathbb{R}$ is superlinear at zero and sublinear at infinity, e.g., $f(s) = \min(|s|^r,|s|^p)$ with $0 0$, non-existence and multiplicity results are obtained.
We prove that if $F$ is a Lipschitz map from the set of all complex $n\times n$ matrices into itself with $F(0)=0$ such that given any $x$ and $y$ we have that $% F\left( x\right) -F\left( y\right) $ and $x-y$ have at least one common eigenvalue, then either $F\left( x\right) =uxu^{-1}$ or $F\left( x\right) =ux^{t}u^{-1}$ for all $x$, for some invertible $n\times n$ matrix $u$. We arrive at the same conclusion by supposing $F$ to be of class $\mathcal{C}% ^{1}$ on a domain in $\mathcal{M}_{n}$ containing the null matrix, instead of Lipschitz. We also prove that if $F$ is of class $\mathcal{C}^{1}$ on a domain containing the null matrix satisfying $F(0)=0$ and $ρ(F\left( x\right) -F\left( y\right) )=ρ(x-y)$ for all $x$ and $y$, where $ρ\left( \cdot \right) $ denotes the spectral radius, then there exists $γ\in \mathbb{C}$ of modulus one such that either $γ^{-1}F$ or $γ^{-1}\overline{F}$ is of the above form, where $\overline{F}$ is the (complex) conjugate of $F$.
We are concerned with the asymptotic analysis of positive blow-up boundary solutions for a class of quasilinear elliptic equations with absorption term. By means of the Karamata theory we establish the first two terms in the expansion of the singular solution near the boundary. Our analysis includes large classes of nonlinearities of Keller-Osserman type.
We study codimension growth of infinite dimensional Lie algebras over a field of characteristic zero. We prove that if a Lie algebra $L$ is an extension of a nilpotent algebra by a finite dimensional semisimple algebra then the PI-exponent of $L$ exists and is a positive integer.
We study polynomial identities of algebras with adjoined external unit. For a wide class of algebras we prove that adjoining external unit element leads to increasing of PI-exponent precisely to 1. We also show that any real number from the interval [2,3] can be realized as PI-exponent of some unital algebra.