Cardinal functions of Pixley–Roy hyperspaces

The Topology of Systems of Hyperspaces Determined by Dimension Functions

Given a non-degenerate Peano continuum X, a dimension function D : 2∗ → [0,∞] defined on the family 2 X ∗ of compact subsets of X, and a subset Γ ⊂ [0,∞), we recognize the topological structure of the system 〈2 ,D≤γ(X)〉α∈Γ, where 2 X is the hyperspace of non-empty compact subsets of X and D≤γ(X) is the subspace of 2 X , consisting of non-empty compact subsets K ⊂ X with D(K) ≤ γ.

Local cardinal functions of H-closed spaces

The cardinal functions of pseudocharacter, closed pseudocharacter, and character are used to examine H-closed spaces and to contrast the differences between Hclosed and minimal Hausdorff spaces. An H-closed space X is produced with the properties that |X| > 22 ψ(X) and ψ(X) > 2ψ(X).

Three Cardinal Functions Similar to Net Weight

The purpose of this paper is to introduce and investigate cardinal functions called pseudonet weight, weak net weight, and weak pseudonet weight. These are similar to but generally smaller than net weight. We look at how these cardinal functions relate to hereditary Lindelöf degree, hereditary density, and spread, and we study their behavior under products. An important and useful cardinal func...

Are social welfare functions ordinal or cardinal ?

Numerical solution of the Sturm-Liouville problem by using Chebyshev cardinal functions

In this manuscript, a numerical technique is presented for finding the eigenvalues of the regular Sturm-Liouville problems. The Chebyshev cardinal functions are used to approximate the eigenvalues of a regular Sturm-Liouville problem with Dirichlet boundary conditions. These functions defined by the Chebyshev function of the first kind. By using the operational matrix of derivative the problem ...