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On theorems for weak solutions of nonlinear differential equations with and without delay in Banach spaces

100%

Gomaa A. M.

Commentationes Mathematicae

2007

tom 47

nr 2

In the present work we give an existence theorem for bounded weak solution of the differential equation \[ \dot{x}(t) = A(t)x(t) + f (t, x(t)),\quad t \geq 0 \] where \(\{A(t) : t \in I\mathbb{R}^+ \}\) is a family of linear operators from a Banach space \(E\) into itself, \(B_r = \{x \in E : \|x\| \leq r\}\) and \(f \colon \mathbb{R}^+ \times B_r \to E\) is weakly-weakly continuous. Furthermore, we give existence theorem for the differential equation with delay \[ \dot{x}(t) = \hat{A}(t) x(t) + f^d (t, θ_t x)\quad \text{if}\ t \in [0, T], \] where \(T, d \gt 0\), \(C_{B_r} ([-d, 0])\) is the Banach space of continuous functions from \([-d, 0]\) into \(B_r\), \(f_d\colon [0, T] \times C_{B_r} ([-d, 0]) \to E\) weakly-weakly continuous function, \(\hat{A}(t)\colon [0,T] \to L(E)\) is strongly measurable and Bochner integrable operator on \([0,T]\) and \(θ_t x(s) = x(t + s)\) for all \(s \in [-d, 0]\).

Existence and Topological Properties of Solution Sets for Differential Inclusions with Delay

100%

Gomaa A. M.

Commentationes Mathematicae

2008

tom 48

nr 1

We consider the problem \(\dot{x}(t) \in A(t)x(t) + F (t, θ_t x))\) a.e. on \([0, b]\), \(x = \kappa\) on \([-d, 0]\) in a Banach space \(E\), where \(\kappa\) belongs to the Banach space, \(C_E ([-d, 0])\), of all continuous functions from \([-d, 0]\) into \(E\). A multifunction \(F\) from \([0, b] \times C_E ([-d, 0])\) into the set, \(P_{f_c} (E)\), of all nonempty closed convex subsets of \(E\) is weakly sequentially hemi-continuous, \(θ_t x(s) = x(t + s)\) for all \(s \in [-d, 0]\) and \(\{A(t) : 0 \leq t \leq b\}\) is a family of densely defined closed linear operators generating a continuous evolution operator \(S(t, s)\). Under a generalization of the compactness assumptions, we prove an existence result and give some topological properties of our solution sets that generalizes earlier theorems by Papageorgiou, Rolewicz, Deimling, Frankowska and Cichoń.

Ograniczanie wyników

2 Commentationes Mathematicae

2 Gomaa A. M.

1 2008

1 2007

Wyniki wyszukiwania

On theorems for weak solutions of nonlinear differential equations with and without delay in Banach spaces

Existence and Topological Properties of Solution Sets for Differential Inclusions with Delay