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Włodzimierz J. Charatonik

Publications and source records attributed to Włodzimierz J. Charatonik.

3 recordsLinked to original sources

The projective Fra\"ıssé limit of the family of all connected finite graphs with confluent epimorphisms

We investigate the projective Fra\"ıssé family of finite connected graphs with confluent epimorphisms and the continuum obtained as the topological realization of its projective Fra\"ıssé limit. This continuum was unknown before. We prove that it is indecomposable, but not hereditarily indecomposable, one-dimensional, Kelley, pointwise self-homeomorphic, but not homogeneous. It is hereditarily unicoherent and each point is the top of the Cantor fan. Moreover, the universal solenoid, the universal pseudo-solenoid, and the pseudo-arc may be embedded in it.

math.GN↗

Projective Fraïssé limits of trees with confluent epimorphisms

We continue the study of projective Fraïssé limits developed by Irwin-Solecki and Panagiotopoulos-Solecki by investigating families of epimorphisms between finite trees and finite rooted trees. Ideas of monotone, confluent, and light mappings from continuum theory as well as several properties of continua are modified so as to apply them to topological graphs. As the topological realizations of the projective Fraïssé limits we obtain the dendrite $D_3$, the Mohler-Nikiel universal dendroid, as well as new, interesting continua for which we do not yet have topological characterizations.

math.GN↗

Projective Fra\"ıssé limits of trees

The following paper has been withdrawn from consideration for publication because there are mistakes. In particular, Theorem 3.9 does not hold. Examples were found of finite trees with monotone epimorphisms which do not amalgamate. Further, finite rooted trees with monotone epimorphisms do not amalgamate. A revision, with additional co-authors A. Kwiatkowska and S. Yang, is posted on arXiv ({\it Projective Fra\"ıssé limits of trees with confluent epimorphisms} 2312.16915). In that article, it is shown that the family of finite trees having ramification vertices of order at most 3 with monotone epimorphisms does form a projective Fra\"ıssé family and the topological realization of its Fra\"ıssé limit is the Wa\. zewski dendrite $D_3$. Further, two families of finite rooted trees with restrictions on what confluent epimorphisms are allowed are also shown to form projective Fra\"ıssé families. The topological realization of the Fra\"ıssé limit of one of these families is shown to be the Mohler-Nikiel universal dendroid. We continue study of projective Fra\"ıssé limit developed by Irvin, Panagiotopoulos and Solecki. We modify the ideas of monotone, confluent, and light mappings from continuum theory as well as several properties of continua so as to apply to topological graphs. As the topological realizations of the projective Fra\"ıssé limits we obtain the dendrite $D_3$ as well as quite new, interesting continua for which we do not yet have topological characterizations.

math.GT↗