Tangles of string typically become knotted, from macroscopic twine down to long-chain macromolecules such as DNA. Here, we demonstrate that knotting also occurs in quantum wavefunctions, where the ...

Based on these eigenfunctions there is constructed a special system of functions that already forms the basis. However the obtained system is not already the system of the eigenfunctions of the ...

Examples are given of noncompact Riemannian manifolds having nonnegative Ricci cuvature and infinitely many square integrable eigenfunctions for the Laplace operator. This monthly journal, begun in ...