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On the Operational Solution of a System of Fractional Differential Equations

Takači, Dj., Takači, A. (2010)

Fractional Calculus and Applied Analysis

MSC 2010: 26A33, 44A45, 44A40, 65J10We consider a linear system of differential equations with fractional derivatives, and its corresponding system in the field of Mikusiński operators, written in a matrix form, by using the connection between the fractional and the Mikusiński calculus. The exact and the approximate operational solution of the corresponding matrix equations, with operator entries are determined, and their characters are analyzed. By using the packages Scientific Work place and...

On the order of magnitude of Walsh-Fourier transform

Bhikha Lila Ghodadra, Vanda Fülöp (2020)

Mathematica Bohemica

For a Lebesgue integrable complex-valued function f defined on + : = [ 0 , ) let f ^ be its Walsh-Fourier transform. The Riemann-Lebesgue lemma says that f ^ ( y ) 0 as y . But in general, there is no definite rate at which the Walsh-Fourier transform tends to zero. In fact, the Walsh-Fourier transform of an integrable function can tend to zero as slowly as we wish. Therefore, it is interesting to know for functions of which subclasses of L 1 ( + ) there is a definite rate at which the Walsh-Fourier transform tends to zero. We...

On the points of non-differentiability of convex functions

David Pavlica (2004)

Commentationes Mathematicae Universitatis Carolinae

We characterize sets of non-differentiability points of convex functions on n . This completes (in n ) the result by Zajíček [2] which gives a characterization of the magnitude of these sets.

On the pointwise limits of sequences of Świątkowski functions

Tomasz Natkaniec, Julia Wódka (2018)

Czechoslovak Mathematical Journal

The characterization of the pointwise limits of the sequences of Świątkowski functions is given. Modifications of Świątkowski property with respect to different topologies finer than the Euclidean topology are discussed.

On the power-series expansion of a rational function

D. V. Lee (1992)

Acta Arithmetica

Introduction. The problem of determining the formula for P S ( n ) , the number of partitions of an integer into elements of a finite set S, that is, the number of solutions in non-negative integers, h s , . . . , h s k , of the equation hs₁ s₁ + ... + hsk sk = n, was solved in the nineteenth century (see Sylvester [4] and Glaisher [3] for detailed accounts). The solution is the coefficient of x i n [(1-xs₁)... (1-xsk)]-1, expressions for which they derived. Wright [5] indicated a simpler method by which to find part of the solution...

On the proof of Erdős' inequality

Lai-Yi Zhu, Da-Peng Zhou (2017)

Czechoslovak Mathematical Journal

Using undergraduate calculus, we give a direct elementary proof of a sharp Markov-type inequality p ' [ - 1 , 1 ] 1 2 p [ - 1 , 1 ] for a constrained polynomial p of degree at most n , initially claimed by P. Erdős, which is different from the one in the paper of T. Erdélyi (2015). Whereafter, we give the situations on which the equality holds. On the basis of this inequality, we study the monotone polynomial which has only real zeros all but one outside of the interval ( - 1 , 1 ) and establish a new asymptotically sharp inequality.

On the range of the derivative of a real-valued function with bounded support

T. Gaspari (2002)

Studia Mathematica

We study the set f’(X) = f’(x): x ∈ X when f:X → ℝ is a differentiable bump. We first prove that for any C²-smooth bump f: ℝ² → ℝ the range of the derivative of f must be the closure of its interior. Next we show that if X is an infinite-dimensional separable Banach space with a C p -smooth bump b:X → ℝ such that | | b ( p ) | | is finite, then any connected open subset of X* containing 0 is the range of the derivative of a C p -smooth bump. We also study the finite-dimensional case which is quite different. Finally,...

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