Existence and uniqueness of solution for initial value problem of first order differential equation involving generalized Lebesgue-Bochner spaces Lp(I,(Xv, II.II))
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We consider a bitopological vector space (X, v, II.II), where (X, v) is a topological vector space, and II.II is a norm defined on X. This paper deals with the existence and uniqueness of solution for initial value problem of first differential equation: (P)( ˙ x(t) = f(t), t is an element of]alpha, beta[ x(alpha) = x1, where the vector valued function f:]alpha,beta[-› X is assumed to be not necessarily in the classical Lebesgue-Bochner space L1(]alpha,beta[, (X, II.II). Here, by the solution of problem (P), we mean a vector valued function x acting from ]alpha,beta[ into X satisfying the conditions: 1) x is absolutely continuous with respect to the norm II.II; 2) x is almost everywhere differentiable on ]alpha,beta[ with respect to the topology v; 3) ˙ x = f(t) almost everywhere on ]alpha,beta[; 4) x(alpha) = x1. For this, we introduce a special class of integrable functions called generalized Lebesgue- Bochner space denoted L1(]alpha,beta[, (Xv, II.II)) containing (in general, strictly containing, [see the example given at the end of the paper]) the classical Lebesgue-Bochner space L1(]alpha,beta[, (X, II.II). Thus, under some conditions on the pair of topologies (v, II.II) , we prove that if f is an element of L1(]alpha,beta[, (Xv,II.II)), then the initial value problem (P) has an unique solution in the above mentioned sense. Finally, we give an example to illustrate the result given in this paper.
Bibliogr. 7 poz.
-  D. H. Hyers, Pseudo-normed linear spaces and abelian groups, Duke Math. J. 5 (1939), 628-634.
-  S. Lahrech, A. Ouahab, A. Benbrik, A. Mbarki, Some Properties of Sequentially Continuous Linear Mappings Acting in Topological Vector Spaces, accepted for publication in IJPAM. Sofia, Bulgaria, 2005.
-  A. Taylor, D. Lay, Introduction to Functional Analysis, Second Edition. Krieger Publishing Company, Malabar, Florida, 1980.
-  A. N. Kolmogorov, C. V. Fomin, Functional Analysis, Nayka, (1976) (in Russian).
-  J. L. Kelly, T. P. Srinivasan, Measure and Integral, Volume 1. Springer-Verlag, New York, 1988.
-  A. J. Weir, Lebesgue Integration and Measure, Cambridge University Press, 1973.
-  J. Mikusinski, The Bochner Integral, Birkhauser, 1978.