On polynomials of least deviation from zero in several variables.
On projection constant problems and the existence of metric projections in normed spaces.
On restricted derivative approximation
On the approximation by compositions of fixed multivariate functions with univariate functions
The approximation in the uniform norm of a continuous function f(x) = f(x₁,...,xₙ) by continuous sums g₁(h₁(x)) + g₂(h₂(x)), where the functions h₁ and h₂ are fixed, is considered. A Chebyshev type criterion for best approximation is established in terms of paths with respect to the functions h₁ and h₂.
On the best approximation properties of -smooth functions on an interval of the real axis (to the phenomenon of unsaturated numerical methods).
On the Convergence of an Algorithm for Discrete Lp Aprroximation.
On the existence and characterization of minimal projections.
On the lower semi-continuity of the set valued metric projection.
On the method of least squares of finding eigenvalues and eigenfunctions of some symmetric operators. II.
On the Number of Best Approximation in Certain Non-linear Families of Functions.
On the Number of Best Approximations in Certain Non-Linear Families of Functions. (Short Communication).
On the Number of Zeros of Functions in a Weak Tchebyshev-Space.
On the rational Tschebyscheff operator.
On the Renorming of a Vector Space Endowed with Two Norms and the Simultaneous Best Approximation Problem.
On the uniform continuity of metric projection
On the uniform convergence and L¹-convergence of double Walsh-Fourier series
In 1970 C. W. Onneweer formulated a sufficient condition for a periodic W-continuous function to have a Walsh-Fourier series which converges uniformly to the function. In this paper we extend his results from single to double Walsh-Fourier series in a more general setting. We study the convergence of rectangular partial sums in -norm for some 1 ≤ p ≤ ∞ over the unit square [0,1) × [0,1). In case p = ∞, by we mean , the collection of uniformly W-continuous functions f(x, y), endowed with the...
On the Uniform Norm of an Arbitrary Coefficient Functional over Finite Dimensional Subspaces of C (D).
On Uniqueness of Best L1-Approximation of Disjoint Intervals.
On upper semicontinuity in good coapproximation
On weak Chebyshev subspaces and Chebyshev approximation by their elements