scholarly journals Sign conditions for the existence of at least one positive solution of a sparse polynomial system

2020 ◽  
Vol 375 ◽  
pp. 107412 ◽  
Author(s):  
Frédéric Bihan ◽  
Alicia Dickenstein ◽  
Magalí Giaroli
2009 ◽  
Vol 51 (3) ◽  
pp. 571-578 ◽  
Author(s):  
G. A. AFROUZI ◽  
H. GHORBANI

AbstractWe consider the system where p(x), q(x) ∈ C1(RN) are radial symmetric functions such that sup|∇ p(x)| < ∞, sup|∇ q(x)| < ∞ and 1 < inf p(x) ≤ sup p(x) < ∞, 1 < inf q(x) ≤ sup q(x) < ∞, where −Δp(x)u = −div(|∇u|p(x)−2∇u), −Δq(x)v = −div(|∇v|q(x)−2∇v), respectively are called p(x)-Laplacian and q(x)-Laplacian, λ1, λ2, μ1 and μ2 are positive parameters and Ω = B(0, R) ⊂ RN is a bounded radial symmetric domain, where R is sufficiently large. We prove the existence of a positive solution when for every M > 0, $\lim_{u \rightarrow +\infty} \frac{h(u)}{u^{p^--1}} = 0$ and $\lim_{u \rightarrow +\infty} \frac{\gamma(u)}{u^{q^--1}} = 0$. In particular, we do not assume any sign conditions on f(0), g(0), h(0) or γ(0).


Author(s):  
D. D. Hai ◽  
R. Shivaji

Consider the system where λ is a positive parameter and Ω is a bounded domain in RN. We prove the existence of a large positive solution for λ large when limx → ∞ (f(Mg(x))/x) = 0 for every M > 0. In particular, we do not need any monotonicity assumptions on f, g, nor any sign conditions on f(0), g(0).


2006 ◽  
Vol 11 (4) ◽  
pp. 323-329 ◽  
Author(s):  
G. A. Afrouzi ◽  
S. H. Rasouli

This study concerns the existence of positive solutions to classes of boundary value problems of the form−∆u = g(x,u), x ∈ Ω,u(x) = 0, x ∈ ∂Ω,where ∆ denote the Laplacian operator, Ω is a smooth bounded domain in RN (N ≥ 2) with ∂Ω of class C2, and connected, and g(x, 0) < 0 for some x ∈ Ω (semipositone problems). By using the method of sub-super solutions we prove the existence of positive solution to special types of g(x,u).


Public Voices ◽  
2016 ◽  
Vol 13 (2) ◽  
pp. 89
Author(s):  
Rachel Lange ◽  
Kimberly Nelson

Despite gains by women in many professional fields, the top level of local government management ranks continues to be populated primarily by man. The percentage of females serving as local government chief administrators has not increased since the 1980s. Little empirical research exists that attempts to uncover the reason for the gender gap. The purpose of this research is to identify some of the obstacles and barriers that affect a woman’s decision to advance her career in local government. Utilizing an online survey, the authors surveyed female chief administrative officers (CAOs), assistant CAOs, assistant to the CAOs, and deputy CAOs in Illinois. The survey results show that barriers such as a male dominated culture and time commitment to work life and family life are preventing females from achieving higher authority. Mentoring proves to be a positive solution to many of the barriers facing women in local government.


1988 ◽  
Vol 9 (8) ◽  
pp. 727-736
Author(s):  
Lan Kun-quan ◽  
Ding Xie-ping
Keyword(s):  

Author(s):  
Yunru Bai ◽  
Nikolaos S. Papageorgiou ◽  
Shengda Zeng

AbstractWe consider a parametric nonlinear, nonhomogeneous Dirichlet problem driven by the (p, q)-Laplacian with a reaction involving a singular term plus a superlinear reaction which does not satisfy the Ambrosetti–Rabinowitz condition. The main goal of the paper is to look for positive solutions and our approach is based on the use of variational tools combined with suitable truncations and comparison techniques. We prove a bifurcation-type theorem describing in a precise way the dependence of the set of positive solutions on the parameter $$\lambda $$ λ . Moreover, we produce minimal positive solutions and determine the monotonicity and continuity properties of the minimal positive solution map.


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