CONVOLUTION EQUATIONS ON THE ABELIAN GROUP $\cA(-1,1)$

The interval $j=[-1,1]$ turns into an Abelian group $\cA(\cJ)$ under the group operation $x+_\cJ y:=(x+y)(1+xy)^{-1},\qquad x,y\in\cJ$. This enables definition of the invariant measure $d_\cJ x=(1-x^2)^{-1}dx$ and the Fourier transform $\cF_\cJ$ on the interval $\cJ$ and, as a consequence, we can consider Fourier convolution operators $W^0_{\cJ,\cA}:=\cF_\cJ^{-1}\cA\cF_\cJ$ on $\cJ$. This class of convolutions includes celebrated Prandtl, Tricomi and Lavrentjev-Bitsadze equations and, also, differential equations of arbitrary order with the natural weighted derivative $\fD_\cJ u(x)=-(1-x^2)u’(x)$, $t\in\cJ$. Equations are solved in the scale of Bessel potential $\bH^s_p(\cJ,d_\cJ x)$, $1\leqslant p\leqslant\infty$, and H\”older-Zygmound $\bZ^\nu(\cJ,(1-x^2)^\mu)$, $0<\mu,\nu<\infty$ spaces, adapted to the group $\cA(\cJ)$. Boundedness of convolution operators (the problem of multipliers) is discussed. The symbol $\cA(\xi)$, $\xi\in\bR$, of a convolution equation $W^0_{\cJ,\cA}u=f$ defines solvability: the equation is uniquely solvable if and only if the symbol $\cA$ is elliptic. The solution is written explicitely with the help of the inverse symbol. We touch shortly the multidimensional analogue-the Abelian group $\cA(\cJ^n)$.

Solvability Criterion for Convolution Equations on a Half-Strip

We obtain the criterion of solvability of homogeneous convolution equation in a half-strip. Proof is based on a new decomposition property of the weighted Hardy space. This result has relations to the spectral analysis-synthesis problem, cyclicity problem, information theory. All data generated or analysed during this study are included in this published article.

Existence and monotonicity of nonlocal boundary value problems: the one-dimensional case

We consider nonlocal equations of the general form \begin{equation} \left(a*u''\right)(\cdot)+\lambda f\big(\cdot,u(\cdot)\big)=0.\nonumber \end{equation} By developing a Green's function representation for the solution of the boundary value problem we study existence, uniqueness, and qualitative properties (e.g., positivity or monotonicity) of solutions to these problems. We apply our methods to fractional order differential equations. We also demonstrate an application of our methodology both to convolution equations with nonlocal boundary conditions as well as those with a nonlocal term in the convolution equation itself.

The Solvability of a Class of Convolution Equations Associated with 2D FRFT

In this paper, the solvability of a class of convolution equations is discussed by using two-dimensional (2D) fractional Fourier transform (FRFT) in polar coordinates. Firstly, we generalize the 2D FRFT to the polar coordinates setting. The relationship between 2D FRFT and fractional Hankel transform (FRHT) is derived. Secondly, the spatial shift and multiplication theorems for 2D FRFT are proposed by using this relationship. Thirdly, in order to analyze the solvability of the convolution equations, a novel convolution operator for 2D FRFT is proposed, and the corresponding convolution theorem is investigated. Finally, based on the proposed theorems, the solvability of the convolution equations is studied.

VLSI Implementation of Digital Filter using Novel RTSD Adder and Booth Multiplier

Finite Impulse Response (FIR) filters are most important element in signal processing and communication. Area and speed optimization are the essential necessities of FIR filter design. This work looks at the design of Finite Impulse Response (FIR) filters from an arithmetic perspective. Since the fundamental arithmetic operations in the convolution equations are addition and multiplication, they are the objectives of the design analysis. For multiplication, Booth encoding is utilized in order to lessen the quantity of partial products. Consequently, considering carry-propagation free addition strategies should improve the addition operation of the filter. The redundant ternary signed-digit (RTSD) number framework is utilized to speedup addition in the filter. The redundant ternary representation utilizes more bits than required to denote the single binary digit because of which most numbers have several representations. This special behavior of RTSD allows the addition along with the absence of typical carry propagation. Xilinx ISE design suite 14.5 is used for the design and validation of proposed method. From the implementation result, the proposed design of FIR filter is compared with other conventional techniques to show the better performance by means of power, area and delay.

Locally Explicit Fundamental Principle for Homogeneous Convolution Equations

In the present paper a locally explicit version of Ehrenpreis’s Fundamental Principle for a system of homogeneous convolution equations f μ j = 0, j = 1; : : : ;m, f ∈ E(Rⁿ), μ j ∈ E′(Rⁿ), is derived, when the Fourier Transforms μ j , j = 1; : : : ;m are slowly decreasing entire functions that form a complete intersection in Cⁿ.