The results presented in this paper concern approximation by smooth functions in the Sobolev spaces defined by means of a modular (1). These spaces can be a natural medium to study the partial differential equations with rapidly or slowly increasing coefficients (i.e. the coefficients are of a nonpolynomial type).
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This paper describes some generalization of modular function spaces Lϕψ defined by a modular Iϕѱ(f) = ∫baϕ (x, ∫dc ψ (y, f (x,y))dy) dx, ([3]). The next part of this paper focuses on using of spaces, defined previously, to introduce Sobolev spaces as a vector subspace of the generalized space Lϕѱ. Some selected properties of these spaces are presented.
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Let C be a ρ-bounded, ρ -closed, convex subset of a modular function space Lρ. We investigate the existence of common fixed points for semigroups of nonlinear mappings Tt : C → C, i.e. a family such that T0(x) = x, Ts+t = Ts(Tt(x)), where each Tt is either ρ -contraction or ρ -nonexpansive. We also briefly discuss existence of such semigroups and touch upon applications to differential equations.
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In this paper we prove the uniform boundedness of the operators of convolution in the Musielak-Orlicz spaces and the density of C[...]in the Musielak-Orlicz-Sobolev spaces by assuming a condition of Log-Hölder type of continuity.
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The purpose of this note is to define and to investigate the generalized Nakano sequence space A(p) and to show that the sequence space A(p) eąuipped with the Luxemburg norm is rotund and posses property-H when p = (pk) is bounded with pk > 1 for all k is an element of N.
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In this paper we obtain an extension of the classical Korovkin theorem in abstract modular spaces. Applications to some discrete and integral operators are discussed.
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By means of terms of a sequence (pn), where pn, n = l,2,..., are pseudomodulars, and by means of an infinite matrix A = [amn ] of non-negative numbers we shall construct the modular spaces XpAos' and Xp^os. Then we shall approximate elements of these spaces by means of terms of a sequence (p.), where p, i = l,2,..., are pseudomodulars. In particular, we will investigate the special cases when pn and pt are singular integrals.
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There are established some conditions for existence of solutions of a nonlinear integral equation Tf =f+g, where T is a convolution-type integral operator.
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Let T be the space of all real double sequences. For a given matrix A and fi-function f we consider two modular spaces connected with strong (A,fi) and | A,fi| summability. This paper contains some generalization of theorems given by J.Musielak and W.Orlicz in [4] and [5].
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We consider the problem of detennining upper bounds for nonns of functions from Orlicz-Sobolev space[...], [...] in tenns of nonns of the space [...] and Orlicz space. The interpolation inequalities of this type are well-known for classical Sobolev spaces [...], [...]and also [1].
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Let r,n be two modulars on L(G), and let W be an abstract set of indices. For nonlinear integral op-erators T(w) and S(w) on L(G), we give sufficient conditions for two methods of summability gen-erated by T(w) and S(w) to be consistent for sequences (f(w)) of functions of L(G), in the sense of modular r.
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There are estimated moduli of continuity of functions satisfying Lipschitz condition with random exponents both in the sense of convergence in probability and convergence in mean. The results are applied to extend Jackson's direct approximation theorem to the case of Lipschitz condition with a random exponent.
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