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Though reciprocity is an important aspect of coercive diplomacy, little is known about whether and when sanctioned countries (i.e., targets) respond to foreign pressure with their own counter-sanct...

This paper considers the approximate controllability for a class of abstract semilinear control systems using a method called surjectivity theorems for nonlinear operator equations under restrictiv...

Economic sanctions constrain targets’ capacity to maintain essential goods imports from foreign suppliers. This research points out that target states may respond to this adverse effect of sanction...

This research examines the relationship between economic sanctions and income inequality of sanctioned states. Economic sanctions have a discernible effect on target income inequality. I argue that such an effect significantly varies across sanctions instruments and economic conditions of sanctioned countries. Data analysis for 152 countries from 1974 to 2011 shows that import sanctions increase inequality of labor-abundant targets, but such an effect disappears in labor-scarce targets, whereas the findings provide no reliable evidence for the effect of export sanctions. The results also suggest that foreign aid sanctions reduce the inequality of targets that are significantly dependent on foreign assistance.

International institutions play a key role in sanctions success. However, little is known about when senders mobilize institutional sanctions and how they induce international institutions to support their sanctioning efforts. Senders may need institutional support when they expect third-party states to engage in sanctions-busting. I suggest that senders anticipate sanctions-busting when they face third-party rivals which also have an alliance tie with targets. The presence of such potential sanctions busters may lead senders to seek institutional support. Also, senders should possess substantial material power to induce member states of international institutions to approve the sanctioning efforts. I assess the theoretical claim of this research by analyzing 1,038 sanctions episodes over the period 1951–2005. The findings support my argument that senders pursue institutional support when they face potential sanctions busters, and the success of their efforts partly depend on their material power.

The purpose of this paper is to find the time optimal control to a target set for semilinear stochastic functional differential equations involving time delays or memories under general conditions on a target set and nonlinear terms even though the equations contain unbounded principal operators. Our research approach is construct a fundamental solution for corresponding linear systems and establish variations of constant formula of solutions for given stochastic equations. The existence result of time optimal controls for one point target set governed by the given semilinear stochastic equation is also established.

We consider a quasilinear wave equation u t t − △ u t − d i v ( | ∇ u | α − 2 ∇ u ) − d i v ( | ∇ u t | β − 2 ∇ u t ) + a | u t | m − 2 u t + μ 1 u t ( x , t ) + μ 2 u t ( x , t − τ ) = b | u | p − 2 u a , b > 0 , associated with initial and Dirichlet boundary conditions at one part and acoustic boundary conditions at another part, respectively. We prove, under suitable conditions on α , β , m , p and for negative initial energy, a global nonexistence of solutions.

What effect does the type of economic sanctions have on sanctions duration? Despite extensive research about their effect on sanctions success, little is known about how sanction types affect the duration of sanctions episodes. I argue that, among different types of economic sanctions, terminating foreign aid to target states (foreign aid sanctions) expedites target capitulation, because it imposes disproportionate costs on elites and crucial regime supporters. However, I also contend that the effect of foreign aid sanctions is rendered indistinguishable from other types of economic coercion over time, as target governments adjust to the adverse impacts of sanctions. The empirical tests using the Threat and Imposition of Economic Sanctions dataset provide supporting evidence for my hypotheses that foreign aid sanctions accelerate target capitulations, but this effect diminishes over time.

In this paper, we deal with the approximate controllability for semi-linear retarded functional integro-differential equations by using the Fredholm theory in Hilbert spaces. We no longer require the compactness of structural operators to obtain the approximate controllability for the nonlinear differential system, but instead we use the theory of interpolation spaces and the regularity of solutions of semi-linear given equations with unbounded principal operators. Finally, based on the properties of general degree theory in infinite dimensional spaces, we investigate the relation between the reachable set of trajectories of the semi-linear retarded functional integro-differential system and that of its corresponding linear system excluded by the nonlinear term.

What effect do the domestic institutional constraints in target states have on sanction outcomes? Other than the narrow focus on political regime type, little is known about how the institutional makeup of target states might affect leaders’ ability to adjust their policies to defy sanctions. We assert that the size of veto players in targets is a crucial yet overlooked institutional factor in explaining sanction effectiveness. We contend that political leaders subject to the approval of multiple veto players are more likely to concede as they are less likely to develop polices to counter the sanctions. We assess the empirical merits of our theoretical claims by combining data on sanctions from the Threat and Imposition of Economic Sanctions data set with the veto points data from the Political Constraints data set. Results from the data analysis for the 1946 to 2005 period indicate that the size of veto players is a significant predictor of sanction success even when we control for political regime type and other major political and economic covariates of sanction effectiveness.

In this paper we consider the energy decay rates for the semilinear wave equation with memory boundary condition and acoustic boundary conditions. Motivated by results of Gerbi and Said-houari (2011, 2008), Li and Zhao (2011), Liu and Chen (2016), Wu etal. (2010) and Lu etal. (2011) we intend to study the energy decay rates for problem (1.1)(1.6). By using the perturbed energy method and Riemannian geometry method, we obtained general energy decay rates

We consider the quasilinear wave equation $$u_{tt} -\triangle u_{t} -\operatorname{div}\bigl(\vert \nabla u\vert ^{\alpha-2} \nabla u\bigr) - \operatorname{div}\bigl(\vert \nabla u_{t}\vert ^{\beta-2} \nabla u_{t} \bigr) +a \vert u_{t}\vert ^{m-2} u_{t} =b|u|^{p-2} u $$ $a,b>0$ , associated with initial and Dirichlet boundary conditions at one part and acoustic boundary conditions at another part, respectively. We prove, under suitable conditions on α, β, m, p and for negative initial energy, a global nonexistence of solutions.

This paper deals with the identification problem for the $L^1$-valued retarded functional differential equation. The unknowns are parameters and operators appearing in the given systems. In order to identify the parameters, we introduce the solution semigroup and the structural operators in the initial data space, and provide the representations of spectral projections and the completeness of generalized eigenspaces. The sufficient condition for the identification problem is given as the so called rank condition in terms of the initial values and eigenvectors of adjoint operator.

This paper deals with the time optimal control problem for semilinear retarded functional differential equations by using the construction of the fundamental solution in the case where the principal operators are unbounded. We also present the maximum principle for controls which are described by the adjoint state corresponding to the linear equations without the condition of differentiability for the nonlinear term.

In this paper, we construct some results on the existence andregularity for solutions of neutral functional di erential equations withunbounded principal operators in Hilbert spaces. In order to establishthe existence and regularity for solutions of the neutral system by usingfractional power of operators and the local Lipschtiz continuity of non-linear term without using many of the strong restrictions considering inthe previous literature. 1. IntroductionLet H and V be real Hilbert spaces such that V is a dense subspace inH. In this paper, we are concerned with the global existence of solution andthe approximate controllability for the following abstract neutral functionaldi erential system in a Hilbert space H:( ddt [(x (t) + (Bx)( )] = Ax ) + f t;x )) + k ); t2(0;T];x(0) = x 0 ; (Bx)(0) = y 0 ;(1.1)where Ais an operator associated with a sesquilinear form on V V satisfyingG arding’s inequality, fis a nonlinear mapping of [0;T] Vinto Hsatisfying thelocal Lipschitz continuity, B: L

This paper investigates the time optimal control problem to a target set for semilinear control systems involving time delays or memories when a principal operator is unbounded by the construction of a fundamental solution and an easy consequence of the definition of real interpolation spaces. A convergence theorem of time optimal controls for the given semilinear retarded system to a point target set is also given.

In this paper, the approximate controllability of the semilinear functional differential equations with unbounded delays is first investigated. Then the regularity of solutions of the given system is addressed. Finally, a simple example to which our main result can be applied is given.

The purpose of this paper is to derive a perturbation theory of evolution systems of the hyperbolic second order hyperbolic equations. We give an example of a partial functional equation as an application of the preceding result in case of the mixed problems for hyperbolic equa- tions of second order with unbounded principal operators.

Sufficient conditions for approximate controllability of semilinear retarded functional control equations are obtained under general conditions on nonlinear terms. To get the main result, we transform the controllability problem into surjectivity results similar to Fredholm alternative for nonlinear operators under restrictive assumptions. Finally, a simple example to which our main result can be applied is given.

In this paper we deal with approximate controllability for semilinear system in a Hilbert space. In order to obtain the controllability, we assume that the system of the generalized eigenspaces of the principal operator is complete in the state space, which has a simple form and can be applied to many examples. Because of its simple form, some examples of controllability of the systems governed by the semilinear equations will be given.

The object of this paper is to construct some results on the control problems for retarded functional differential equations of parabolic type with unbounded principal operators in Hilbert spaces. In order to establish relations between controllability of the given equation and observability of the adjoint system, we investigate the equivalent relation for the completeness of generalised eigenspaces of the infinitesimal generators. Finally, when the control space is a finite-dimensional space, a necessary and sufficient condition for the approximate controllability of retarded equations is given by the so-called rank condition.

The purpose of this paper is to establish existence, unique- ness and a variation of constant formula of solutions for semilinear par- tial functional differential equations with unbounded delays and nonlinear part involving integrodifferetial terms.

The goal of this paper is to obtain the regularity and the existence of solutions of a retarded semilinear differential equation with nonlocal condition by applying Schauder's fixed point theorem. We con- struct the fundamental solution, establish the Holder continuity results concerning the fundamental solution of its corresponding retarded linear equation, and prove the uniqueness of solutions of the given equation. d dt x(t) = A0x(t) + R 0 −h a(s)A1x(t + s)ds +f(t;x(t);x(b1(t));:::;x (bm(t))) + k(t); t� 0; x(0) = g 0 − �(x); x(s) = g 1 (s) − e s �(x); −hs < 0; (NRE) Let H and V be complex Hilbert spaces such that the embedding VH is continuous. Let A0 be the operator associated with a bounded sesquilinear form defined in VV satisfying Gu arding inequality. Then A0 generates an analytic semigroup S(t) in both H and Vand so the equation (NRE) may be considered as an equation in both H and V � . The operator A1 is bounded linear from V to Vsuch that its restriction to D(A0) is a bounded linear operator from D(A0) to H. The function a(�) is assumed to be real-valued and Holder continuous in the interval (−h;0), and f, �, bi(i = 1;:::;m ) are given functions satisfying some assumptions.

This paper deals with the existence and uniqueness of solutions for the nonlinear func- tional differential equations with time delay. The regularity and a variation of constant formula for solutions of the given equations are also studied.

In this paper, we study the optimal control problems governed by the semilinear parabolic type equation in Hilbert spaces. Under Lipschitz continuity condition of the nonlinear term, we can obtain the optimal conditions and maximal principles for a given equation, which are described by the adjoint state corresponding to the given equation without the rigorous conditions for the nonlinear term.

The approximate controllability for the nonlinear control sys- tem with nonlinear monotone hemicontinuous and coercive operator is studied. The existence, uniqueness and a variation of solutions of the system are also given.

We deal with the approximate controllability for the nonlinear functional differential equation governed by the variational inequality in Hilbert spaces and present a general theorems under which previous results easily follow. The common research direction is to find conditions on the nonlinear term such that controllability is preserved under perturbation.

The existence of solutions for a class of strongly nonlinear delay evolution equations is studied. The regularity and a variation of solutions of the given equations are also given.