Displaying 41 – 60 of 213

Showing per page

Complexity of curves

Udayan B. Darji, Alberto Marcone (2004)

Fundamenta Mathematicae

We show that each of the classes of hereditarily locally connected, finitely Suslinian, and Suslinian continua is Π₁¹-complete, while the class of regular continua is Π₀⁴-complete.

Conditions which ensure that a simple map does not raise dimension

W. Dębski, J. Mioduszewski (1992)

Colloquium Mathematicae

The present paper deals with those continuous maps from compacta into metric spaces which assume each value at most twice. Such maps are called here, after Borsuk and Molski (1958) and as in our previous paper (1990), simple. We investigate the possibility of decomposing a simple map into essential and elementary factors, and the so-called splitting property of simple maps which raise dimension. The aim is to get insight into the structure of those compacta which have the property that simple maps...

Continua which admit no mean

K. Kawamura, E. Tymchatyn (1996)

Colloquium Mathematicae

A symmetric, idempotent, continuous binary operation on a space is called a mean. In this paper, we provide a criterion for the non-existence of mean on a certain class of continua which includes tree-like continua. This generalizes a result of Bell and Watson. We also prove that any hereditarily indecomposable circle-like continuum admits no mean.

Continuous decompositions of Peano plane continua into pseudo-arcs

Janusz Prajs (1998)

Fundamenta Mathematicae

Locally planar Peano continua admitting continuous decomposition into pseudo-arcs (into acyclic curves) are characterized as those with no local separating point. This extends the well-known result of Lewis and Walsh on a continuous decomposition of the plane into pseudo-arcs.

Continuous pseudo-hairy spaces and continuous pseudo-fans

Janusz R. Prajs (2002)

Fundamenta Mathematicae

A compact metric space X̃ is said to be a continuous pseudo-hairy space over a compact space X ⊂ X̃ provided there exists an open, monotone retraction r : X ̃ o n t o X such that all fibers r - 1 ( x ) are pseudo-arcs and any continuum in X̃ joining two different fibers of r intersects X. A continuum Y X is called a continuous pseudo-fan of a compactum X if there are a point c Y X and a family ℱ of pseudo-arcs such that = Y X , any subcontinuum of Y X intersecting two different elements of ℱ contains c, and ℱ is homeomorphic to X (with...

Currently displaying 41 – 60 of 213