Harmonic functions, defined as twice continuously differentiable functions satisfying Laplace’s equation, have long been a subject of intense study in both pure and applied mathematics. Their ...

Let X be a normed linear space, Un an n-dimensional Chebyshev subspace of X. For f ∈ X denote by p(f) ∈ Un its best approximation in Un. The problem of strong unicity consists in estimating how fast ...

Initial value problems for first order partial functional almost linear equations with unbounded delay are considered. The functional dependence is represented by the generalized Hale operator with ...