Displaying 121 – 140 of 3918

Showing per page

A locally commutative free group acting on the plane

Kenzi Satô (2003)

Fundamenta Mathematicae

The purpose of this paper is to prove the existence of a free subgroup of the group of all affine transformations on the plane with determinant 1 such that the action of the subgroup is locally commutative.

A measure-theoretic characterization of Boolean algebras among orthomodular lattices

Pavel Pták, Sylvia Pulmannová (1994)

Commentationes Mathematicae Universitatis Carolinae

We investigate subadditive measures on orthomodular lattices. We show as the main result that an orthomodular lattice has to be distributive (=Boolean) if it possesses a unital set of subadditive probability measures. This result may find an application in the foundation of quantum theories, mathematical logic, or elsewhere.

A method for evaluating the fractal dimension in the plane, using coverings with crosses

Claude Tricot (2002)

Fundamenta Mathematicae

Various methods may be used to define the Minkowski-Bouligand dimension of a compact subset E in the plane. The best known is the box method. After introducing the notion of ε-connected set E ε , we consider a new method based upon coverings of E ε with crosses of diameter 2ε. To prove that this cross method gives the fractal dimension for all E, the main argument consists in constructing a special pavement of the complementary set with squares. This method gives rise to a dimension formula using integrals,...

Currently displaying 121 – 140 of 3918